CNC Expo at Collexion - Wednesday, June 13
David Hempy
So, here's where we are currently:
We've made our first cuts on the CNC router, with great results! While there's still work to be done, the hardware side of the machine is functional and nearly complete -- just like the Death Star. We'd like to show off a bit and share what we know so far about running the machine. In particular, we'll show you how to fire up the machine, computer, and controller software; mount a piece of work to be cut; load a g-code program for a simple design; and run the g-code to cut the part.
Completing these steps gets us to a minimal level of making things with the machine. Note that we aren't *designing* any parts yet. Looking ahead, we will to develop our design tools, to elevate our current basic functionality into a truly versatile artistic/engineering toolset.
For this next phase, we are inviting a new group of volunteers to join the project. We need people who thrive on installing various software packages and tinkering with it to figure it out, and ultimately recommending software for us to adopt. Happily, this describes most of Collexion's members. I'll be recruiting volunteers for this Wednesday night to add to our happy crew.
To make this machine truly versatile and powerful, we need to explore the top two layers of software, CAD and CAM:
1. CAD - Computer Aided Design. This is the software you use to design your 2D or 3D model. There's gobs of free, cheap, and absurdly expensive software tools out there, and Collexion has amateurs and experts in several of them. Options includes SketchUp, AutoCAD, Solidworks, Blender, Rhino, Aspire, 3D Studio Max, and many, many more. 3D is sexy, but don't overlook the power of 2D design, particularly for router operations.
It is not critical that everyone using the router and/or MakerBot use the same CAD software. As long as your favorite software can output one of several formats (STL, DXF, DWG, etc.), we should be good. Collexion may or may not acquire licensed CAD software for the membership to use...that is up to us all to decide together.
2. CAM - Computer Aided Manufacturing. This layer of software converts the design you created in CAD to g-code. G-code is a toolpath that tells the robot to move from point to point in space, cutting away everything that isn't part of the final design. (That's for a subtractive process, like our router. For an additive process, like the MakerBot, it is the path through space that builds up everything that *is* part of the final design.) Again, there are lots of software options out there, from free to astronomically priced.
I'll admit that this is the layer I know the least about, and will be looking to others to evaluate and recommend/implement options. My light research has turned up lots of references to free CAM software, but many of these are abandoned projects or of questionable robustness. There are some low- to moderate-cost packages that have strong followings. Nearly all have a free, crippled evaluation version.
I personally anticipate that Collexion will acquire 2D and 3D CAM software for everyone's use -- but again, that is for all of us to decide together.
There are some packages that bundle CAD/CAM together, which is worth considering. However, having those two layers of software separate would allow a very flexible workflow for the group. First, develop your design at home on your own time, using the CAD tools and platform you work best in and are best suited to the type of thing you're building. This might be a ten minute sketch, or a year of development. Then, bring it to the space and convert it to g-code with Collexion's CAM softare, and cut it on the machine.
Well, enough blather. Who's going to be there Wednesday 7-9 for this? Gotta have four folks to make this happen. BTW, if the desire is there but the scheduling is bad, please chime in as well.
-dave
Nikolai Warner
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Dustin Mays
timk
-Tim
Chris Stieha
That's really cool to know it has progressed this far.
Charlie Campbell
I'll be there in spirit!
That's really cool to know it has progressed this far.
Chris Harn
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magicclockshop
Patrick "Kai" Baker
Dave Hempy
Excellent questions, Chris! I’ll answer them below with 95% confidence. If I get part of this wrong, I sure hope someone calls me on it.
-dave
From: coll...@googlegroups.com [mailto:coll...@googlegroups.com]
On Behalf Of Chris Harn
Sent: Monday, June 11, 2012 10:09 AM
To: coll...@googlegroups.com
Subject: Re: CNC Expo at Collexion - Wednesday, June 13
This is cool I hope to be there as well!
> Questions (maybe save answers for wednesday):
> At the moment you are using Mach 3 as CAM software right?
Mostly right. We are using Mach 3 (and I expect we’ll license it Wednesday to remove the 500-line limit)…but that’s not the CAM software. Mach 3 is the machine controller, that processes g-code. The CAM software that generates g-code comes before that, and we don’t have that figured out yet.
> Oversimplified, is the computer program just sending G-Code as ascii out the parallel port?
No.
Mach 3 is interpreting the g-code, “understanding” how to get from (x=0, y=0, z=0) to (x=1, y=3.375, z=0), in terms of how many tiny steps to turn the motors on each axis. (not to mention how fast to send those steps, if the emergency stop has been hit, how fast the machine can accelerate, and many other factors…) Oh, and do it in realtime accuracy.
> Would pasting gcode into a text file and printing it out the lpt1 port?
Nope.
(In fact, I think you could argue this parallel port is not an lpt port (that is, not a *printer* port), but that’s a bit too geeky for me)
To oversimplify a bit, the motor on each axis is connected to a pair of pins on the parallel port. (Ok…there’s more to it than that, but bear with me.) The computer sends a “blip” to the stepper motor on an axis, and that motor advances one step. On our machine, it takes about 2000 steps to move an inch. Mach 3 is the one generating all those blips, which keeps the computer *very* busy.
There is no intelligence downstream of the computer. The Gecko controller and steppers don’t know what they’re doing, where they are, or where they are going. All they do is take one step forward or one step back, as commanded by the computer.
> Can you break the CNC with bad code?
Absolutely! :-D
Crashing the router against the hard stops shouldn’t actually *break* the machine, but is…shall we say…not very graceful. Running a cutting bit into a clamp or too fast for the material can break the bit or tear up the fixtures. Probably the most common problem we’ll have is ruining your project 95%, I’m guessing.
We’ll touch on all these ideas Wednesday night. I’ll share everything I know, and will be eager to learn from everyone else. See you there!
-dave
timk
> learn about the MakerBot, if someone will step up to lead that session.
everything (dry PTFE-based lube as recommended by Makerbot), but it
didn't seem to solve the issues we're having. There are a lot of
variables right now. Something (or several somethings) in this list
need to be rejiggered:
- ReplicatorG version
- skeinforge version
- skeinforge Dimension plugin (may require different firmware)
- Print-o-matic 5D volumetric printing settings
- Z-axis calibration (wrong steps per millimeter?)
- firmware version (newer skeinforge versions may require custom third-
party firmware?)
On my last test print, the makerbot's X-axis belt popped out, so it
doesn't move in the X direction. I didn't have time to disassemble the
XY carriage to put it back in place.
It looks like the aluminum heat spreader is way more efficient at
dissipating heat than the adhesive foil used with the ABP. We used to
set the HBP to 110C in our start.gcode file, but it looks like that
needs to be cut to 100C. If it's set to 110C, the 'bot won't begin to
print because it's waiting for a temperature it may not be able to
hit. I've modified the start.gcode in the "collexion" skeinforge
profiles already, but if you start a new profile, you'll have to make
this change yourself.
Dustin Mays
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David Hempy
It might could be that I am overthinking this thing, but here’s the
agenda for tonight’s expo. Hope to see you all there!
-dave
CNC Router Expo and Primer
June 13, 2012, 7-9 PM
Collexion Hackerspace - Loudon at N. Limestone, behind Bullhorn.
Disclosures - 90% accurate, money-back guarantee.
Introductions all around.
Cookies!
Quick project history - Fall to date
Idea / proposal / approval / fundraising / build / cut!
- Summer, 2011: Idle banter about how cool a CNC router at Collexion would be.
- Aug 26: http://collexion.net/wiki/CNC created ("Goal: by Oct 1st") (currently grossly out of date)
- Sept (?): Go-ahead from Collexion directors.
- Oct 15: Google Groups - Collexion-CNC first post: ("Minute [sic] - 10/15/2011 meeting"). Joe's 4x4 plans purchased.
- Nov 18: After just a few days of fundraising, pledges totaling $3050 (plus cookies!) received, exceeding $3,000 goal
- Dec: Planning continues, refining budget and detailed Bill of Materials.
- Jan 16, 2012: First parts - Three MDF carriages, cut by James Lindsay on his former machine.
- Feb 12: Construction of the welded steel base starts.
- Feb - April: Lots of parts arriving and bulk of construction.
- May 11: Machine moves under own power on two of three axes! Wo0T!
- June 2: Make: Sawdust -- first cut!
- June 13: CNC Expo - first "unveiling" to Collexion in general.
Historic re-enactment of first cut! (hearing & eye protection, dust collection)
Salute to the CNC Team: James, Dustin, Jason, John, David, Ron, Brennan, and Mike!!! (Who did I miss?)
Encourage incoming volunteers.
Salute to our funders:
Jason, Nick, Dave, Derek, Aaron, Dustin, Edgar, Ashley, Noah, Todd, John G, Lori, James, Mike D, Mike A, John M, Kent, Asian Steev, John Y, Steve (APBurner), Janine
And now, the Meat of the Meeting (w/ apologies to our vegetarian friends!): Systems Overview. Follow us on a tour of the entire machine, starting roughly from the cutting bit and working our way back through each system to the computer and software.
2. Hold downs - track, screws, clamps.
3. Router bit - various types. downcut, compression, others.
4. Router - spindle speed. Future relay.
5. Z axis - leadscrew
6. Stepper motors - 200 steps, 2000 microsteps
7. Carriages
8. X axis - gantry - perspective
9. Rack and pinion - gear reduction - speed for torque
10. Y axis - v-rails, hard stops
11. Limit / Homing switches - Hall effect switches - Emergency Stop switches
12. Slaved Y / A axes - racking, homing
13. Cables - Energy chain
14. Enclosure
15. Gecko G540 motor controller
16. DC Power supply
17. Parallel cable - straight-through, not printer
18. Computer - basic, parallel port, circuits, blown hard drive, startup (thank you, Chris!)
19. CNC controller software. Mach 3 / EMC. NC vs. CNC. steps, config.
20. G-code - by hand
21. CAM - DeskProto, Cut2D, Cut3D...
22. CAD
23. Inspiration! www.cnczone.com http://www.joescnc.com/forums The world. Suggestions?
Cut other G-code designs, demo use of Mach3. Explore settings
Demo wizards, cut hall effect mounts - pockets, drilling
What might YOU make with it?
- Photo albums
- Roundtable
Hazards:
- Dust inhalation (MDF, plastics, fiberglass)
- Eye injury
- Entrapment (don't buy from cops)
- Pinching
- Hearing
- Others?
Looking ahead:
- Post To Do list in shop and online
- Invite new volunteers to join the old gaurd, esp. w/ CAM/CAD choices.
- MAKE!!!
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