Adventures in vacuum repair

When using the Shop-Vac the other day I noticed all the dust I was sucking up was being blown out the back of the vacuum… all over me.  Intrigued and filthy, I decided to investigate…

I emptied the vacuum and took the filter outside to knock as much dust and crud off of it as I could.  I employed the standard method of smacking it on the building and quickly twisting it back and forth in the breeze being careful to stay upwind so as not to breathe the fine and disgusting particles liberated.

When replacing the filter I immediately found the problem, or more accurately I didn’t find a key part of the vacuum cleaner.  The filter retainer was missing.  Without it, whatever the vacuum sucks up can shoot through the open bottom of the filter through the impeller and get blown all over me.  Fabricating a quick replacement from parts on hand took no time at all.  Sure, I could have bought the replacement part for $9 and had it next day from Amazon, but where is the fun in that?

I found a suitable scrap of 1/4″ acrylic onto which I traced the inner and outer diameters of the filter.

Using a jigsaw with a coarse blade I cut just outside the outer diameter.  Cutting acrylic or polycarbonate with a jigsaw (or CNC) can be tricky, friction heats the blade and the chips can weld the opening closed behind the cut as pictured here.  This piece was easily broken away with my hand, but I’ve had polycarbonate heal itself apparently stronger than the uncut material when cutting too fast without any coolant or compressed air to clear the chips.

Using a ruler and pen I measured and marked the center of the diameter along several angles.  Using the hammer and punch, I punched the mark for drilling (the dimple allows the drill to center more accurately).  This level of precision was not necessary but I find striking things with a hammer fun and habits like punching before drilling are good to reinforce.

I clamped the burgeoning new cover in the vise and drilled the center hole.  The bolt hardware is the ubiquitous 1/4″-20 (1/4 inch diameter, 20 threads per inch, super common stuff), so I’m going to drill the hole a little larger, 3/8″ to make it easy to slide on and off.  I don’t want to drill a hole that large to start with in the acrylic because it will catch a lot and cause chipping or cracking, so I started with a smaller 1/8″ drill and worked up through a couple sizes.

Now I need to install a mounting rod in the bottom of the vacuum cleaner.  Marking the center of the bottom of the vacuum cleaner filter holder was even easier.  I just connected the lines between the edges of retaining tabs on the outer edge.  This plastic is thin and soft enough to drill directly with the 1/4″ bit.

Then I installed the filter holder pin by putting a 4″ 1/4″-20 bolt through a lock washer, then a fender washer then fed it through the hole from behind (from the vacuum cleaner side) to stick out the bottom.  I followed that with another fender washer, a lock washer and a nut.  The fender washers sandwich the plastic to spread out any load and prevent cracking around the hole.  The lock washers keep the nuts tight even under the vibration of the running Shop-Vac.

The filter slides over the outside, and the cover slides over the bolt to seal it in place.  Another fender washer, lock washer, and convenient wingnut secure the assembly with a good tight seal.

At this point the filter replacement was functional but by no means done.  Workshop88 is a makerspace, and that means nothing is done unless you’ve used the laser or a 3D printer, so Christine engraved the lid.

IMG_5309

Voila!

I could have easily ordered the appropriate replacement and had the fresh new part the next morning, but by creating one myself I get the satisfaction of a job well done, and I was able to vacuum up the acrylic chips from the jigsaw and drill right away.

D. Scott Williamson
Compulsively Creative

 

 

Who likes FREE software?

Image result for who likes free

It’s amazing how much you can get and do for FREE today.  With a modest laptop or desktop computer and access to the internet, you have a huge selection of free operating systems and high quality software to do just about anything you want to do.

Depending on the application, I install most of this software on any new machine I set up.  I like them all, my favorites are marked with a ““.

Updated November 14,2018 marked with 11/14/18
Updated November 21,2018 marked with 11/21/18
Updated December 7, 2018 marked with 12/7/2018

Cross platform

For me “cross platform” usually means Ubuntu Linux and Windows 7 or 10, but much of the software listed here is available on Mac and other versions of Unix/Linux too.

General Purpose / Utility

  • Firefox Mozilla browser (and web debugger)
  • Chrome (or Chromium on Linux) Google’s powerful browser
  • TightVNC Great VNC remote desktop server, client, and java client for portability, features file sharing and scale-able remote desktop windows.
  • VirtualBox Virtual machines are awesome!  Want to try a new OS in your existing OS? Want to try some software before installing it for good?
  • WinRAR File compression/decompression tool that handles all the formats with great Explorer integration
  • AVG Antivirus Free Free antivirus software that has saved me many times.  Recently, AVG has tried harder to get me to buy the full version but the free antivirus is really the star of their offering.  As with any antivirus software, watch for false positives too (files you want to keep ending up in the virus vault)

Communication

  • FileZilla Mozilla ftp and sftp client and much more
  • WireShark Network sniffer, inspector, debugger

Programming

  • Visual Studio Code Free powerful IDE for developing all kinds of code
  • Eclipse IDE Powerful cross platform IDE for C++, Java, and other languages
  • Arduino IDE IDE for developing and debugging software for Arduino and other embedded platforms
  • KDiff3 Best diff and merge tool, works on files or directories, and only tool to feature 4 way merging with re-sync.
  • Git Distributed source control
  • Python One of the most popular, well supported scripting languages
  • Ruby Another powerful popular scripting language

Office Suites

Art

  • ImageMagick Powerful image manipulation tools, especially from the command line or in batches
  • Gimp Powerful bitmap graphics tool (comparable to Adobe Photoshop)
  • InkScape  Powerful bitmap and vector tools (comparable to Corel)
  • Darktable Virtual light table (11/14/18)
  • Pencil2D Hand drawn animation studio (11/21/18)

Audio/Video

  • Audacity Powerful mult-itrack audio editing and mixing tool
  • VLC Super portable cross platform audio/video/CD/DVD… player
  • youtube-dl Download and convert videos and playlists from YouTube and many other video sites to audio or video files
  • Any Video Converter Easily convert video between many formats with defaults to target most mobile devices
  • Handbrake Video transcoder, rip your DVD’s and watch them on your mobile devices
  • LAME mp3 encoder
  • FFmpeg video encoder and much more

3D Modeling

  • OpenSCAD ♥♥♥ “The programmer’s 3D modeler”, my go-to tool for creating most models for 3D printing.
  • Meshmixer Super powerful 3D model creation and editing tool (UI is a little quirky)
  • Meshlab Powerful 3D mesh editing & visualization tool (even quirkier)
  • Blender Powerful 3D modeling, animating, and rendering software

3D Printing

  • Slic3r Prusa Edition 3D printer slicer software, enhanced by Josef Prusa
  • Ultimaker Cura Another powerful slicer for 3D printing
  • Pronterface (available in the bundle) 3D printer controller software
  • Octoprint control your 3D printer over your network with powerful cool plugins, record time lapse videos, and even run from a Raspberry Pi.
  • GPX tool that will allow you to convert gcode to x3g files for Makerbot printers

CAD/CAM

Windows

General Purpose / Utility

  • Everything by Void Tools – Index all your hard drives and find files instantly
  • WinDirStat Simply the BEST disk/filesystem usage tool
  • AstroGrep Search file contents for strings with nice interface
  • ImgBurn Burn CD’s and DVD’s
  • Notepad++ Great editor with lots of features and plugins
  • SciTE Another good editor I use for Ruby development
  • Rapid Environment Editor Best tool for editing Windows environment variables (remember to run as Administrator)
  • 7-zip Another file compressor/decompressor with Explorer integration
  • Drive Image XML Disk backup and recovery tool (my favorite for Windows XP and older machines)
  • AutoHotKey Programmable hotkey macros
  • Putty Free ssh, scp,sftp,telnet and other tools for secure communication
  • HxD Hex editor
  • Win32DiskImager Used to write and backup USB, SD, MicroSD cards (my favorite Raspberry Pi image tool)
  • YAWCAM Webcam software: motion detection, time lapses, live streams…
  • VirtualDub Powerful video editing software with plugins and scripting
  • iTunes Install iTunes to get Bonjour which will enable you to access machines by their host names (i.e. raspberrypi.local) on Windows
  • Cygwin Linux tools and lightweight environment in Windows
  • MSYS/MinGW Another Linux tools and environment for Windows
  • fldigi spectrum analysis and decoding software for amateur radio
  • Magical Jellybean KeyFinder – Recover Windows, Microsoft Office, and other installed software serial numbers.  An excellent tool for data recovery or if you need to re-set up a system from scratch. (12/7/2018)

Linux

OS

There is a HUGE variety of Linux flavors to choose from, https://distrowatch.com/ is a great website to see what’s popular and read about the pro’s and con’s of each of them. (Check out this GNU/Linux Distributions Timeline from Wikipedia)  One of the great things about Linux is that most distributions (“distros“) have live CD’s available; download a disk image, copy image to USB drive or burn a CD or DVD, reboot your computer from the USB drive or disk and you can try the OS before committing to a full installation.  You can also run them from (and later install them to) a virtual machine like VirtualBox to try them, keep them around, and copy them between physical machines, even if they are running different operating systems.

Some of my favorite distributions

  • Ubuntu (Debian) – Most popular
    • Lubuntu – Lightweight version of Ubuntu
    • Xubuntu – Another lightweight version with Xfce desktop
    • Linux Mint – Popular Ubuntu derivative
  • CentOS (Fedora)
  • Puppy Linux – ♥♥♥ Super lightweight, brings life to old machines

Software

  • KDirStat File and directory size analysis tool (similar to WinDirStat)
  • LinuxCNC CNC controller (11/21/2018)
  • MachineKit a fork of LinuxCNC that has additional features and supports the Beagle Bone Black controller (11/21/2018)
  • Most of the Linux tools I use are cross platform and in the list above

Command line

  • htop interactive process manager that can run in a terminal
  • ncdu No Curses Disk Usage – disk usage tool that can run in a terminal
  • mc Midnight Commander file browser/copy tool with great terminal ui

Stand alone boot disks (CD/DVD/USB)

  • CloneZilla Best disk/partition/file system backup and recovery tool (my favorite)
  • Ultimate Boot CD Huge collection of powerful tools on one live bootable CD

Online resources

I hope you found something useful here!  If you have any suggestions I’d love to hear about them, please comment or contact me at Workshop 88 (info@workshop88.com).

D. Scott Williamson
Compulsively Creative

25 Minute CNC digitizing probe

On a whim I decided to whip together a collet mounted Z depth probe for my CNC machine.

It took 25 minutes and works GREAT!

Construction


Select 1/4″ aluminum rod to fit my 1/4″ collet


Measure length that I think will fit into the collet with clearance for the switch and wiring, marked with a pencil.


Clamp into a vise and cut with hacksaw. Be sure to wear eye protection. I used hardboard to protect the soft aluminum from being gauged and pressed out of shape in the vise.


Use a hacksaw to cut a square notch into one end. I cut just off center down the middle by eye about half an inch then cut sideways from the thinner side to remove D shaped slug leaving a D shaped semicircular shaft.


The rod was slightly oversized and would not fit properly into my collet.

 
I clamped it into the chuck of my drill press and used a file on the spinning rod to reduce its diameter until it fit. Files are designed to be pushed away from the operator so be sure to pay attention to the direction of rotation and file, this results in pushing the file away from you pressed against the right side of the cylinder in a standard drill press.  Of course, only test the fit when the drill press is off and stopped.


You could also use sandpaper if a file is not available, but it will take longer.


I used the file to take sharp corners off business end.


Align the switch with the cutaway in the end of the rod and mark the height of the mounting holes in your switch on the round part of the D.
Notice the pencil marking near and on my finger.


Use the hacksaw or file to cut a notch in the back round D part at the height you marked.  This will be needed to hold the switch securely in place later.


I selected a long length of stranded wire with an RCA connector on one end from the junk wire drawer. Just about any flexible wire will suffice, just remember that the wire will repeatedly flex with the motion of the machine so should not be too stiff and ideally should be stranded, not solid conductor type.


I grabbed a microswitch and soldered the wires to the “C” common and “NC” normally closed connections. You want the switch normally closed so that if there is ever a fault or broken wire the CNC digitizer will detect the open circuit right away and interpret that as contact with the workpiece while probing.. If you wire it normally open and a connection is broken then the CNC machine will try to probe right into your workpiece. (unless, you make a mistake I did, but more on that later…)

To attach the switch to the D shaped end of the aluminum rod. I lashed the switch to it using a twist tie, for a more permanent connection add a drop of epoxy between the switch and metal.


Strip the insulation off a twist tie.  It is easiest to remove 1/2″ – 3/4″ sections until you have a fully stripped steel wire rather than try to strip very long sections in a single go.


Thread the twist tie through the mounting hole in the switch twice.


Slide the D shaped portion of the aluminum rod into the wire loop and start twisting the wire ends by hand.  Be sure the wire seats in the slot you sawed or filed in the back of the round part of the “D”.


Tighten the wire using pliers being careful not to break the wire or delicate plastic part of the switch. You may need to wiggle the switch in order to seat it properly on the rod aligning the hole with the groove for a tight fit.

At this point I also bent the end of the metal switch plate slightly a few mm from the end to provide more springy direct contact right under the tip of the center of the probe to ensure the metal arm is what makes contact and closes the switch rather than pressing the microswitch under the arm directly down on the workpiece.


Tie the electrical wire to the shank for a strain relief and attach the wire to your machine so that it does not get pinched or caught in moving parts.


Completed probe elevated and engaged.

Wiring and configuration

Wire your probe. I threaded mine conveniently through the spiral compressed air hose.
Connect your new probe to your controller’s digitizer input.

Note: Wiring and configuring your motion controller is not included in the 25 minutes.
I had already wired and configured a digitizer for Mach 3 using a Xylotex motion controller on the parallel port.

You will need to configure your CNC controller to accept a probe and wire it accordingly. On my parallel port connection on the Xylotex motion controller I wired a 10k resistor from the probe pin to +5 and wired the switch between the probe pin and ground so when the switch is normally closed, the pin reads “0”, and when the switch is depressed the circuit to ground opens and the pin is pulled up to +5 and reads a logic “1”. I offer this as an example for my configuration but you should check your controller and software manuals to determine correct wiring for your equipment.


In Mach 3 I can test my digitizer probe by looking at the diagnostics screen. When I press the button I can see the digitizer input light up telling me that the switch is working and the software is configured correctly.

Test function and repeatability


To test the digitizer function I issue a G31 Z-1 F10 command. This tells Mach 3 to move Z to -1 at a feedrate of 10 inches per minute (ipm) and to stop when the digitizer is engaged.


To test reliability and repeatability I issued this command 12 times and recorded the Z height where the probe engaged each time.  I entered these measurements into a spreadsheet to calculate the minimum, maximum, average and standard deviation of the samples… this probe was reproducible with a standard deviation of 0.000824″, under a thousandth of an inch. This is great for woodworking or PCB engraving.

Test engraving on a non flat surface

To really test it I mounted a piece of melamine on a set of 1/4 inch shims to create a severe slope and performed a standard engraving cut.

As you can see, any slope or irregularity is a nightmare for engraving with a “V” bit. High portions of the work surface are engraved too deeply and lower portions may not be engraved at all resulting in an uneven line width.

I used ScorchWorks G-Code Ripper to generate a new gcode file from the first one that included probing and compensated for the measured work surface elevation in the g-code.


When I engraved the new g-code (on the right) it started by probing the surface, then asks the user to switch to a cutter bit and completes the engraving operation. This sample was engraved to a uniform depth which is an improvement but I still didn’t know how to set an accurate zero depth so it is too deep.

The final missing piece was to figure out a way to register the probe zero height to the cutter z height.


My collets do not allow reproducible tool height location so I had to find a workflow to zero each bit during the machining process. Here is what I found:

Make sure your gcode contains an M6 manual tool change operation and that your controller pauses and allows you to change bits, jog, and reset zero z (or alternative similar functionality)

  1. Install the probe in the router
  2. Move to the X Y origin over the workpiece
  3. Probe to the surface G31 Z-1 F10
  4. Zero X, Y, Z
  5. Start the g-code with probe operations, it will probe the surface, and then pause (be sure your router does not get turned on or it will rip your probe wiring to shreds)
  6. When you resume the gcode it will pause again for the tool change.
  7. Replace the probe with the cutter
  8. Manually jog to X=0 and Y=0
    (In my Mach 3 controller I cannot execute gcode like G0 X0 Y0 during a tool change, I have to jog manually)
  9. Manually jog z to the work surface and manually zero Z.
    I use a 0.001″ thick JOB rolling paper as my machinist mentor taught me. Place the paper under the bit and move it down one thousandth at a time until it just pinches the paper then either type .001 into the Z DRO or just zero Z if a thousandth of an inch is not critical.
  10. Jog Z up a little to clear the workpiece
  11. Turn on the router
  12. Resume g-code program to complete the machine operations

These steps are meant for you to understand the operations I had to go through with my machine to get great results. You may have to adjust these steps for your software/controller.

It works perfectly!

The source artwork is really not intended for engraving, it’s just something I grabbed to run some tests, please don’t judge the it too harshly.  You can see that the depth of cut is uniform across the finished piece.  This would engrave just as well on a curved or irregular workpiece as well.


This is particularly impressive considering how deliberately un-level the workpiece was fixtured.

Not just for engraving…

This isn’t just helpful for engraving, I recently used probing to correct for the irregularities in 4′ x 8′ sheets of 1/4″ plywood.  These sheets can be warpy and wavy by over 1/2″ on a large part.  Normally I would have to cut many passes with the 1/4″ bit potentially deep into my spoilboard to ensure good cuts.  My machine is slow and those extra passes cost a painful amount of time.  With probing I was able to cut each part out of the irregular 1/4″ thick material using a .3″ cutting depth and a 1/4″ endmill in a single pass with excellent results, several times faster than it would have taken me in the past.


Here is a custom organizational shelving unit I made for a friend, it turned out great.

Links:

ScorchWorks G-Code Ripper
Mach 3 CNC Controller
Xylotex CNC Controller and stepper motors

It took less than 25 minutes to make the probe while taking all these pictures along the way!  It took under 20 minutes the second time (see below), and it took waaaay longer to write this blog post.

I hope this was helpful, or at least entertaining.

D. Scott Williamson
Compulsively Creative

P.S. Test your probe and wire it carefully!


At the beginning of the first large scale plywood cut my CNC machine made several successful probes of the surface then plowed into the table with slow deliberate force destroying the probe switch. 
Upon close inspection, the alligator clips I hastily used to mount the probe for initial tests were still in use and shorted together bypassing the fail safe and switch operation resulting in the crash.  It’s a good thing that it did not create a dangerous situation.
I was able to re-cut the end of the rod and install a new switch in under 20 minutes which after careful rewiring has operated reliably ever since.

Why Workshop 88 Rocks

I just had another experience Thursday evening reminding me why makerspaces are so great. I needed a very custom spring, but didn’t know how to make it. (It was to remove backlash in the gearbox of a stepper motor driving a robot to play a Theremin, but that doesn’t matter.)

I had the stepper in my hand – since it’s always easier to discuss something concrete – and asked member Bill if he knew anything about making springs. He did, but not the kind I needed. We talked about mandrels and springback, and threw out ideas about how to design a form to wind what I needed.

And then he pulled some music wire from a cabinet and started bending it by hand into very roughly what we thought we needed. That physical strawman let us pull and twist and point and talk about which direction the forces were acting and how to anchor it and how a spring like that really works. After a delightful session of technical banter, I had a LOT more insight into the spring I needed plus the eye-opener that I could just make it by hand! I grabbed some wire and a pair of pliers, and in 15 minutes had a spring that did exactly what I needed.

A fun technical discussion and exploration with a friend, and going from a show-stopper problem to a perfect solution for a few pennies’ worth of materials – it doesn’t get much better than that. And that’s why we hang out at makerspaces.

The project I needed the spring for is another great, if darker example of what happens at the space. An old lonely, dusty Theremin has lived in the back room for years, and I brought it out to see if I could make it work. It had just started to play its first eerie notes, and I was showing it to whoever wandered by, when somebody – a visitor, whose name I don’t recall – said “It would be neat to have a robot play it.” Whoa. That would be so frickin’ cool that even though I needed a new project like I needed a hole in the head, the Theremin playing robot was off and running. Here’s a clip of it playing a scale a couple of weeks later.

I bet lots of makerspaces have stories of whole projects that started by somebody musing “Wouldn’t it be cool if…”.  I guess we’re all suckers for that. 🙂

Prusa i3 MK2S 3D printer kit assembly time lapse videos

Prusa i3 MK2S 3D printer kit assembly time lapse videos

If you’ve ever wanted to see someone assemble a 3D printer from the ground up, I’ve captured every detail, sped it up, and set it to music just for you:

Link to 300x time lapse video (longer, more detail, different background music):
20170323 GoPro Prusa i3 MK2 assembly and print (300x time lapse)

The videos were captured using a GoPro Hero 3 Black in time lapse mode taking a wide angle high definition image every 5 seconds to a 64GB micro SD card.  The camera was mounted to a tripod using parts printed on the Replicator 2 and powered using a USB hub.  The resulting 30fps HD videos were created at 400% and 200% speed respectively.

History…

In 2012 I bought a MakerBot Replicator 2 for my father, which he graciously offered to keep at my house (he’s absolutely the BEST sharer).  He has since moved to a larger house and in December 2016 we happily moved the 3D printer to it’s new and rightful home in his shop where it has been getting good use making parts for an interesting capacitive network antenna power coupling project, and lots of little toys for the grand kids.  It was a great turn-key printer, able to easily slice and print models with its simple intuitive software.  Unfortunately without a heated bed and with limited head temperature it could only print using PLA. This left me without convenient access to a 3D printer, but gave me the opportunity to expand my 3D printing horizons.  I’d been considering buying one for a while, but finally I needed to make a decision.

The search…

For me, selecting a new 3D printer was as difficult as buying a new car.  There are a lot of decisions to make: Cartesian or delta? Retail, kit, or clone? Open or closed source? Which hotend? Cooling fans? Heated bed? Which materials (PLA, ABS, PETG, Nylon…)? What software can be used? and the biggie… How much do I want to spend?

I started my search with the usual “top 10” lists and “3D printer” roundup articles.

# 1 in All3DP top 10 in 2017
(All3DP is totally worth subscribing to by the way)
#1 in Make Magazine 2017 3D printer comparison
Make Magazine review:
Toms 3D review:
If you are interested in 3D printing and are not familiar with Tom, you should be, check out TOM’s 3D  website for some of the best, balanced, scientific reviews and comparisons of 3D printing components, printers, and filaments:
Tom‘s YouTube Channel:
Tom is also a moderator on Google+‘s fantastic 3D Printing group:

I didn’t have to look for very long before one machine started to tick all my boxes:

  • Open Source
  • Kit (and assembled versions available)
  • Cartesian
  • Auto mesh bed leveling
  • Part cooling fan (for PLA)
  • Heated bed (for ABS and other materials)
  • Multi-material
  • Multi-slicer,
  • Affordable
  • … and as an added bonus it has a 4 color upgrade coming later this year.

The Prusa i3 MK2

The machine…

The Prusa i3 MK2 is the latest printer designed by RepRap legend Josef Prusa, and the one at the top of the 2017 best 3D printers lists all over.  If you are not familiar with RepRap (http://reprap.org/) , it is a community of hardware and software makers who have been advancing open source 3D printing for the last couple of decades.  The basic concept behind RepRap is to create a machine capable of creating copies, or improved copies, of itself.  We all have that community to thank for democratizing and popularizing 3D printing to the point where fused filament 3D printing became commercially viable for the public (that, and a couple patents expiring).

Josef has been at the heart of two of the most popular recent open source 3D printer designs: the Mendel, and the Prusa (his namesake), each model undergoing several successful iterations and improvements.  In 2009 Josef Prusa opened shop and began selling printers and kits.  Today, true to his RepRap roots the latest machine, the Prusa i3 MK2 is used to print parts for customers printers in Prusa Research’s “build farm”.

Josef Prusa in Prusa Research’s build farm where Prusa printers are printing Prusa printers.

If you’d like to know more about the printer check out the Prusa website.

The wait…

I was going to order it over Christmas break 2016 but was waffling. I wasn’t sure if the printer was getting too much hype, or if I should get a dedicated dual head printer, or if I should just grab a turn-key printer like a Taz from a local store.  That delay would cost me a lot of time.  I eventually committed to ordering the Prusa i3 Mk2 kit in late January for a whopping $773 (USD) including shipping, an extraordinarily modest price.  Due to high demand and limited supply capacity for parts like the custom heated bed, I would have to wait 3 months.  This was not a surprise, Prusa was very clear about the lead time for their printers.  I received the printer late March.

The assembly…

By now I hope you have watched the assembly video(s).  I could have ordered the printer fully assembled and calibrated for an extra $200 (and extra lead time) but part of the reason I wanted an open source printer is to easily modify and improve it, and for that reason I wanted to know each nut and bolt personally.  It took roughly 8 hours, 5 good beers, 3 cats, and a dog (all featured in the videos) to assemble, test, and calibrate the machine.  The tree frog took 3 1/2 hours to print.  I had already read all the assembly instructions while waiting for the printer, and learned a LOT from watching Tom’s 6 part series about building the cheapest possible clone of the Prusa i3 MK2. (16 1/2 hours of interactive YouTube live streams!!! The clone was eventually named “Dolly” by someone in chat for the first cloned sheep of the same name)

  1. Prusa i3 MK2 live assembly: p1, Y-axis
  2. Prusa i3 MK2 3D printer clone live assembly: p2, X & Z Motion
  3. Prusa i3 MK2 3D printer clone live assembly: p3, X & Y Motion
  4. Prusa i3 MK2 3D printer clone live assembly: p4, Wiring and Printbed (mechanics finished!)
  5. Prusa i3 MK2 3D printer clone live assembly: p5, Electronics and Firmware!
  6. Prusa i3 MK2 3D printer clone live assembly: p6, final setup and first print!

If you decide to get the Prusa i3 MK2 kit or assemble a clone, here are some tips…

  • When there is a captured nut, POUND that nut into place before assembling the parts!!! Both Tom and I had the upper nut from the part cooling fan come loose and bounce around inside assembled parts for tens of minutes before carefully getting it seated.
  • Read ahead.  There are a few steps that provide instruction regarding previous steps like “but don’t over tighten”, or other things that may be should have been said in advance.
  • Look at all the pictures and stay organized.  The instructions are done VERY well in the “Ikea” style.  There are many details that you can only get from the pictures.
  • Be careful to use the correct length/size fasteners, rods, etc.
  • Review each step when done to make sure you didn’t skip or overlook anything.

The quality…

The print quality is amazing.

I haven’t had a lot of time to print many models yet but the resolution and quality of the first PLA print of the tree frog are far and away better than anything I’ve seen before.  It’s only 50mm wide but the surface is so smooth from the .5mm layer height, and the underside is flawless due to the part cooling fan.  The details in the eyes, nostrils, and hips are impressive too.  I’ve also printed a Raspberry Pi case, camera mount, (for OctoPi) and computer stand mounts in ABS.  I’ll be printing some drone parts soon in PETG and ABS, and bought some Nylon to play with.  I’ve tried Slic3r and Cura model slicing software used to convert models to g-code files for 3D printing.  I  preferring Slic3r which was provided by Prusa pre-optimized for this printer, but they are both very good tools.  Stay tuned to blog.workshop88.com for more of 3D printed projects in the future.

Finally, on the topic of Dolly, and a home made clone…

Even though I just bought, assembled, and am still coming up to speed on my fantastic new printer, the idea of building a clone for 1/4-1/3 the price (somewhere in the $250 range) has me and several friends on the verge of starting a group clone build.

Thanks!

Thanks to Kevin Meinert of subatomicglue for letting me use his awesome music in the videos.  If you would like to hear more, visit www.subatomicglue.com.

If you’re interested in building a Prusa or another 3D printer, or a clone, or discussing 3D printing, check out Workshop 88 on Google groups, Slack, or come by our weekly open house any Thursday night after 6:30pm.  Details can be found here.

D. Scott Williamson
Compulsively creative

Maker of CamBam supports Workshop 88 makerspace!

HexRay supports Workshop 88 with a complimentary
CamBam site license & member discount!

Workshop 88 would like to extend a big thank you to HexRay for supporting the our CNC efforts by allowing us unlimited use of CamBam on club Windows and Linux computers plus a discount on CamBam to Workshop 88 members.

For more information about CamBam, check out their website: http://www.cambam.info/

From the website:

CamBam is an application to create CAM files (gcode) from CAD source files or its own internal geometry editor. CamBam has many users worldwide, from CNC hobbyists to professional machinists and engineers.
CamBam currently supports the following:

  • Reading from and writing to 2D DXF files.
  • 2.5D profiling machine operations with auto-tab support
  • 2.5D pocketing operations with auto island detection
  • Drilling (Normal,Peck,Spiral Milling and Custom Scripts)
  • Engraving
  • True Type Font (TTF) text manipulation and outline (glyph) extraction.
  • Conversion of bitmaps to heightmaps
  • 3D geometry import from STL, 3DS and RAW files
  • 3D waterline and scanline machining operations
  • Extendable through user written plugins and scripts

Be sure to check out their CamBam bundles with Mach 3 controller and CutViewer too.  Personally, I purchased the full CamBam + Mach 3 + CutViewer bundle; I couldn’t beat the price and I’ve been happy with them to this day.

As if that wasn’t good enough: “Unlicensed CamBam installations will continue to work after the 40 evaluation uses are up and allow editing drawings and viewing toolpaths.  However, g-code output is limited to 1000 lines, so another option is for people to work on designs at home, then bring them in to the group’s licensed computers to generate g-code.”

This level of support from HexRay is fantastic and something Workshop 88 greatly appreciates!


I have been using CamBam as my go-to CAD-CAM software for many years, to see a sampling of the kinds of things it can do, take a peek at some of my personal CamBam projects:

3D vacuum forming mask mold master for independent movie

Utility shelf for beverages and keys

Wall artwork – Wooden V

Engraved Bahr family crest

Atari Adventure engraved sign

Philosophy Custom Guitars engraved sign

Working miniature TV

Halftone portrait

Stay tuned to see CamBam powered Workshop 88 CNC projects!

…and on behalf of Workshop 88:

THANK YOU Andy @ HexRay!

If you’d like to find out more about Workshop 88, please contact us:
http://blog.workshop88.com/interact-with-us/ or stop by our weekly open house any Thursday evening after 6:30pm.

D. Scott Williamson
Compulsively Creative

3D Printing PLA on a flexible metal build plate

3D Printing PLA on a flexible metal build plate

By D. Scott Williamson

I love 3D printing.  I’ve designed and printed hundreds of models on the Replicator 2 and have developed many useful skills and techniques. The Replicator 2 has a non heated polycarbonate build plate with MakerBot emblems laser cut into one side and the other side is frosted.

I don’t care for having the MakerBot logo in relief on the bottom of my prints so I print on the frosted side of the platform.

These are rafts but I don’t like having the MakerBot logo embossed on my work.

This worked well for hundreds of prints but eventually, scraping the prints off the platform smoothed the rough surface and parts started sticking harder and harder to the build plate.  Ultimately they stuck so hard that the force required to get a spatula or razor under a part started cutting grooves into the build plate.

Two of the most common 3D printing problems are related first layer adhesion to the build platform…

If the first layer does not bond well enough it can result in corners lifting especially for broad parts on unheated platforms.  In the worst cases the part breaks completely free from the platform partway through a print leading to a stringy mess, wasted time and filament, and in rare cases the PLA can stick to and damage the insulation on the print head.

Catastrophe! Lifted corner, parts broke free, filament everywhere, and damaged thermal insulation on the print head.

If the first layer bonds too well to the build platform the part or platform may be damaged when removing the part.  When using blue tape, it may not be possible to completely remove the tape from the part.

I started using blue painters tape and Aqua Net hairspray on the build plate.  I found this combination to work well with PLA, though I’m not sure how necessary the hairspray is.  The problems are that the tape is damaged when removing most prints so needs to be reapplied frequently and can be difficult or impossible to remove from the bottom of finished parts.

Blue tape stuck to part.

Sometimes it’s impossible to remove all the tape residue.

Blue tape doesn’t last long and requires sticky messy maintenance.

I considered a heated build plate, and glass or metal build plates when the idea occurred to me to try to use a flexible metal build plate. I conducted several experiments using a cable chain model that is challenging to print due to fine detail and thin parts that need to bond well in the first layer.

Experiments

Experiment #1: Aluminum flashing with 2 coats of hairspray dried with heat gun and held by binder clips

First I tried aluminum flashing with hairspray.

  1. Measured and cut the aluminum on a paper cutter and nibbler to perfectly fit the build plate

    Aluminum flashing on roll with Replicator 2 build plate

    Rough cut aluminum.  Use gloves, sheet metal is sharp.

    Cut aluminum to size on the paper cutter.

  2. Rolled flat

    Thin sheet aluminum was curled and needed to be flattened.

    Rolling the thin rolled sheet aluminum flat with pipe on foam.  A towel could have also been used underneath the material.

  3. Cleaned with alcohol to remove oils/grease

    Cleaned the sheet aluminum with ammonia and alcohol.

  4. Coated one side with a thin film of hairspray, let it dry, and applied a thicker coat of hairspray

    Two coats of Aqua Net hairspray applied.

  5. Dried the hairspray with heat gun

    Used heat gun to rapidly dry the hairspray.

  6. Clipped aluminum to build plate with binder clips at the edge

    Aluminum plate clamped to build platform.  (The clip in the upper right corner is about to get knocked off.)

  7. Leveled the build plate to account for the thickness of the aluminum plate
  8. Printed a test

    The PLA bonded weakly to the platform and the parts detached easily in the second layer.

    The upper right and lower left clamps had to be moved because the print head knocked them off.

The nozzle interfered with some of the clips and knocked them off.  The PLA did not adhere to the build plate.  Failure.

Experiment #2: Aluminum flashing with wet hair spray and binder clips

Aluminum flashing with wet hairspray yielded the same results.  Failure.

Experiment #3: Aluminum flashing with glue stick held by clips

Using the back side of the same build plate I used a generous layer of glue stick.

  1. Using the back of the cut aluminum plate from Experiment #1
  2. Coated the plate with glue stick
  3. Clipped aluminum to build plate with binder clips at the edge where the nozzle would be less likely to interfere with them

The PLA adhered wonderfully and the print turned out great.
When done I removed the aluminum plate and was able to remove the print by bending the plate – Success!
But the aluminum does not lay flat and the part left dimples in soft thin aluminum plate before letting go.  I need a stronger material.

Experiment #4: Steel sheet with glue stick held by clips

I scrounged around and found a stiffer steel plate salvaged from a magnetic children’s book many years ago.  I did not try to cut the steel plate to fit the platform because I don’t have a shear and did not want to dull my paper cutter cutting steel.  I can cut the steel on the metal shear at Workshop 88.

  1. Using paper towels, I cleaned the steel plate with ammonia to be sure to remove oil or grease, then with alcohol, and finally with tap water
  2. Coated the plate with glue stick
  3. Clipped steel plate to build plate with binder clips at the edge where the nozzle would not interfere with them
  4. Leveled the build plate to account for the difference in thickness between the aluminum and steel plate
  5. Printed another test

The print turned out great!

But the plastic clips that hold the build plate to the printer are raised causing the plate to be irregular and warped and not flat against the polycarbonate platform beneath it.

If you remove a print by flexing the steel it pops right off but it is still possible to dimple the steel this way.  The dimples can easily be gently pounded out with a broad hammer with the steel on a flexible surface like a neoprene mouse mat or a towel.  Parts firmly attached to the steel are easily removed using a spatula and/or a razor so dimpling turned out to be a non-issue.

Experiment #5: Steel sheet with glue stick held by magnetic sheet

To get the platform to lay flat on the platform I attached a sheet of flexible rubbery plastic “refrigerator magnet” material originally intended to be a furnace vent cover to the platform with double sided tape.

  1. Cut magnet to size
  2. Attached magnet to build plate using double sided tape and pressed it flat using a rubber roller
  3. Aligned the steel plate with the platform and when laid flat the magnet holds it firmly and flat
  4. Leveled the build plate to account for the additional thickness of the magnet layer
  5. Coated the plate with glue stick
  6. Printed another test

Best results yet!

Excellent first layer adhesion with fine detail.

The build plate is flat and level, firmly attached to the platform in the center without using clips which makes it very easy to insert into and remove the plate from the printer.  The finish on the bottom of every part is smooth and shiny, far better even than when printing with a raft.

Even though others reported using a coating of glue stick up to a dozen times, I found reused glue stick not to adhere well.  Adding layers of glue builds up, so every couple of prints I wipe the plate down with a wet paper towel before adding a new layer.

I’ve added alignment markings to the build plate to help install the plate consistently, to help center parts, and to help apply glue only where it’s needed for each print.

 Examples:

Markings help guide application of glue and placement of parts in MakerWare software.

Printed right where expected, with a beautiful first layer and finish quality on the bottom without a raft.

Extremely challenging pinhole lens print

This pinhole lens is .2mm thick and each hole is printed separately with 2 shells then the rest is filled in, if any pop off the build plate it will stick to the hot end and gather the rest into a blob of plastic.

This folding phone/tablet stand (http://www.thingiverse.com/thing:692523) is a favorite model in my house.  It’s a hinged phone/tablet stand that prints fully assembled. If you look carefully you can see that there is some slight curling. The plastic is pulling upward at the corners and even though it has not detached from the build plate it is deflecting it slightly up off the magnet.

The finish quality of the base is comparable to printing on glass.

Not every print has been perfect though, this is another phone/tablet stand that started to curl. The print head caught one corner and moved the entire build plate on the magnet. You can see it continued to print offset before I stopped it. It is impressive that it moved the whole build plate without detaching from the platform. I was able to reprint this model successfully. Only a heated bed or chamber can really prevent this issue entirely, but a stronger magnet may require more force to move.

Future work

  • Cut the build plate(s) to size on the shear at Workshop 88. The build plate is still larger than the platform and must bend to go over at least one of the platform holding clips.
  • Cover the entire platform with magnetic material.  The current magnetic material does not cover the entire platform, it is what I had on hand.
  • Find stronger magnets.  The print quality is wonderful but it is still possible for corners of large parts to lift the platform off the magnetic base while staying attached to the platform.
  • After I started printing on steel I found PRINTinZ’s flexible build plates.  I haven’t used them but check them out! http://www.printinz.com/printinz-3d-printer-plates/

Thanks for reading, and good luck with your 3D prints!

D. Scott Williamson
Compulsively Creative

Animatronic owls

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Workshop 88 member Anna Gillespie created a series of animatronic owls for an event at the public library where she works. The owls were controlled with arduinos using servo motors and a wav shield for the sound of the owl hoot.  Some of the owls turned their heads and some of them flapped their wings in addition to hooting. This was a great project to watch from start to finish; thanks, Anna, for sharing with us!

CAD CAM tutorial

CAD CAM tutorial
by D.  Scott Williamson

This tutorial will show you how to use Computer Aided Design and Computer Aided Manufacturing or CAD CAM tools to create and preview a Gcode file of the Workshop 88 logo that can be run in a 3 axis CNC Mill.

Background

There are 5 main types of machine operations

  1. Engrave (follow path): The tool tip will follow the 3D path provided.
  2. Profile: The tool edge will follow either the inside or outside contour of a path down to the specified depth.
  3. Pocket: The tool will remove all the material within a contour down to the specified depth.
  4. Drill: A drill routine will be executed at each point location.  Drill routines come in 2 flavors:
    1. “Peck” used with drill bits, drills to successively deeper depths liftig the bit out of the work regularly to clear chips from the flutes.
    2. “Spiral” used with endmills that are a smaller diameter than the finished hole.
  5. 3D relief: The tool tip will remove material above a 3D surface usually specified in a 3D model or a 2D height map image.  There are two main modes:
    1. “Waterline” similar to inverted pocket operations where bulk material is efficiently removed outside the 3D model to a number of stepped depths resembling waterline in a topological map.  Typically used in a first pass with a large roughing bit to remove the bulk of the material.
    2. “Raster” moves the tip of the bit smoothly over the model in a raster pattern.

Gcode is a “numerically controlled programming language” which is why a Gcode file extension is typically .nc.  It is a human and machine readable text file.  You will rarely if ever need to look at or edit the Gcode.

Overview

This tutorial will demonstrate Engrave, Profile, and Pocket operations, which are the most popular.

There are 4 steps to this tutorial:

  1. Create a .svg file containing paths needed for machine operations
  2. Create machine operations
  3. Export Gcode
  4. Simulate, visualize and validate

Continue reading

T-Kit 1380 Kit Build: Part 2

Today, I’ll be continuing my 80m transceiver build that I started in T-Kit 1380 Kit Build: Part 1.

At the end of the last post, the board looked like this:

The full board

The full board

Today I’ll be moving on to the VFO section of the board.  A VFO, or variable frequency oscillator, is the circuit that allows you to tune a radio.  This particular VFO is based on a Collpits oscillator, and can tune over a 50-70 kHz range centered on a frequency determined by the component values.  The frequency range shown in the image may seem a bit strange.  This transceiver can be built to cover that 50-70 kHz range somewhere near 3.5 MHz to about 3.75 MHz.  The short explanation is that the frequency we’re interested in is shifted by the frequency of the VFO to an intermediate frequency of 8 MHz, where we can do filtering and amplification at a single fixed frequency.  Since a lot of circuit characteristics are frequency-dependent, performance is much better if the components can be selected for just one frequency.

schematic

The majority of the components are supplied with the kit, so their values are fixed.  One of them, an inductor, I had to wind myself.  Since this phase required quite a few components, I decided I’d lay them out before I started.

components

Rather than start building immediately, I decided to wind the inductor first, so I could get that out of the way.  The instructions specified 28 turns of the green #28 enameled wire on the red toroid core.  I had to count the turns several times to be sure.

inductor

The inductance of the coil is dependent on a lot of things, including the material the core is made of, the diameter of the core, the number of windings, and the spacing between the windings.  Later on in the build, I tweak the range covered by the transceiver by adjusting the coil spacing.

phase-2-complete

From this point on, it was simply a matter of stuffing the board and soldering, as per the instructions.  The one thing I would have changed was the process for doing initial testing of the inductor.  They have you tack a couple leads to the pads you’re going to use, and then tack the inductor to those.  Unless your inductor is wildly off, you’re not going to be rewinding it, so I would have skipped that step and just soldered it in directly at the beginning.

The testing of phase 2 was relatively simple, because I’m using a frequency counter.  I just hooked up the frequency counter, and adjusted the spacing of the turns on the coil I mentioned before until the VFO covered the range between 4.470 MHz and 4.391 MHz.

I’ll talk more about it in the next post about the transmit mixer and filter, but that provides an actual range of 3.530 MHz to 3.609 MHz.  This includes the QRP CW calling frequency at 3.560 as well as W1AW’s code practice sessions transmitted on 3.5815.  It does not include the main CW DX window between 3.500 and 3.525 MHz, but I’m still working on getting my Amateur Extra license, so I’m not authorized for that part of the band anyway.