Cutting foam sheets... with a needle!

[ironkane]

Almost ready to roll! While I'm waiting on the good folks at Spark Concepts (http://www.spark-concepts.com/sale/) to resolve the one issue that's really holding me back...initializing a ESC with the PWM output of the control board, I thought I'd share a few more photos.

I based all the tool heads around the Needle Cutter as positioning it is the most complicated of the bunch. I'm shooting for not having to adjust my X or Y homes every time I swap tools. The Pen Holder isn't 100% complete. I need to add some springs above and below the linear bearings with the uppers being slightly stronger so that I maintain good contact with the surface while still being able to lift slightly to overcome drag. I'll add a Drag Knife toolhead later on.

I've come to the somewhat painful conclusion that I need to redesign my Controller Enclosure. I want to include the JTechPhotonics Laser Driver Module into the design. Murphy had struck again when this redesign occurred to me initially. The mounting hole for the driver almost matched the holes that secured the lid of the control box. If they had matched, all I would have had to do is expand the box by adding a middle wall section between lower and the lid. Oh well, at least filament is fairly cheap. The redesign shouldn't take more than a couple hours at the most. Probably half that.

All I got for now.

 

[Michael9865]

ironkane, Looks nice.

I finally finished getting my upgrades done to my MPCNC. After updating to the new Middle Assy and the updated Z-Axis I could not get the new Middle Assy to square up. I got frustrated after fighting it, meaning disassembled and re-assembled it multiple times. I walked away from it for a while and then life and a new Anet A8 got in the way. I got back to it on Tuesday, I loosened the 5″ bolt and nut a little and I heard noise like something seating. Low and behold I checked it with my square to discover that the gantry pipes were now aligned. Tightened the bolt back up and it was still square. I also added the 12v power supply to replace the LiPo battery that I was using for the new Needle Cutter since I had everything apart already. I will do some test cutting either later Thursday or Friday depending on how my schedule plays out.

Here are the aides that I printed to help me put the square on the rails easier. I don't think my clumsy hands were helping me. I will be adding them to Thingiverse later, I will share the link here when the stl is up loaded.

https://www.thingiverse.com/thing:2869566

 

[ironkane]

I wish I had those when I was truing up mine! I didn't have a 3D printer then either. Ended up using 2 carpenters squares bolted together.

 

[jhitesma]

So yesterday was the 3 year anniversary of my first CNC experience success. I figured it would be years until I could afford to build an actual CNC machine, or even 3D printer...so I tore apart some old CD drives, ordered some cheap stepper controllers, dusted off a beat up Arduino Mega I'd retired from a quadcopter...and built a tiny 1.5"x1.5" pen plotter.

It worked...but I was pretty unimpressed with GRBL on the mega and universal gcode sender. And I never managed to design a Z axis for it which left it little more than a proof of concept and a nice introduction to the very basic basics of CNC.

I still have it - I've taken the mega off for other projects but the rest of it still sits on top of my desk in my shop.

What shocked me was when just a few months later I finally managed to save up enough money to get myself a 3D printer kit that December. And just 2 months after that found myself starting to print parts for a MPCNC.

So I haven't touched grbl in about 3 years...I've been happily using Marlin for my MPCNC. But...I'm starting to feel a little limited by it. I really want multiple coordinates (at least machine and work coordinates separated) and while I could rig up a z probe to use Marlin's autoleveling...I'd really like more flexible probing for finding work piece edges and doing tool changes as well as engraving/carving on non-flat surfaces. So...I'm starting to look at other options.

Last week I grabbed a pine64 single board computer I got cheap off kickstarter and have yet to use for anything (I had originally hoped to use it on my living room TV for skype to let me parents talk to their granddaughter - but it's performance for that was sub-par.) Hooked it up to my RAMPS board and installed cncjs on it since I saw they now support Marlin.

Getting cncjs up and going was fairly easy...I've been using node.js quite a bit at work lately so the ecosystem was familiar to me...if you haven't worked with node and npm and nvm before it could be a bit confusing but the docs for cncjs walk you through the basics very simply. I was able to pull up cncjs in a browser on my shop computer and it mostly works!

Though, I can't seem to get work coordinates to function with my old version of Marlin, and due to how Marlin queues commands it's still not quite like a "real" CNC controller. Jogging is non-optimal, the progress display is nice but not as accurate as it would be with something like grbl or tinyG, and overall there are just a number of compromises.

I still love Marlin for the needle cutter. I really think it's the way to go for that application, the servo control for the needle cutter rocks and being able to keep a bunch of plans on SD and fire off cuts from the LCD without a computer is wonderful.

But as I start to do more traditional CNC work with the machine...I want to try other options.

So I broke down and spent $20 on a grbl CNC shield/UNO combo off Amazon. Over the next few weeks I'll be experimenting with it on the machine and trying a few control options. cncjs is the obvious first since I'm already using it with Marlin. But I also want to try bCNC (which I was able to run on the pine64 but use remote x to display it on my macbook with xQuartz) and chilipeppr both of which can do cnc autolevel for engraving/cutting on non-flat surfaces as well as supporting multiple coordinate systems. If there's interest I'll start a new thread to share what I do since it's not really needle cutter related (I will probably keep using Marlin for needle cutting - at least for now - since I'm not sure if grbl/CNC shield can handle servo control, and the LCD/SD is really nice for repeatedly cutting the same thing over and over.)

 

[ironkane]

I'll be the first to admit that I do not want to delve in deep in to CNC Controllers. I just want them to be easy to setup and run. I don't want to have to customize the firmware. So I am pretty happy with the GRBL board I got from Spark Concepts http://www.spark-concepts.com/cnc-xpro-controller-v3/ and it was the cheapest of the 3 controllers that OpenBuilds sells at $129 or $119 at Spark Concepts. I like the simplicity of GRBL. If and when the Spark support resolve the problem I'm having with PWM having too high a starting voltage to initialize the ESC...I'm really going to love it.

 

[Michael9865]

I believe in lifelong learning, but learning software and programming hurts my brain a little. LOL
Good luck with your endeavor jhitesma. Also looking forward to your updates, did I really just type that.

 

[nhk750]

Over 150,000 views! Got to be a record.

 

[dkj4linux]

Well, shoot... I guess my earlier posting got lost in the sudden forum changeover this morning

Fresh back from a 4-day fishing trip, I found you guys had posted some really interesting stuff...

nhk750, I'm glad you stopped in. Are you a CNC'er? 150,000+ posts and nearly 200 pages (previous page specs) is really mind-blowing to me as well. I notice the "view counter" has finally started moving again... it had been stuck at 150, 253 views since the server migration began. But, until my post of this morning, it appeared no posts had been lost. Oh, well...

Jason, I know you'll have fun with GRBL. My C-beam machine is set up with that same Uno, CNCshield, and GRBL combo but it sits, built/tested/calibrated... but unused, until I get my act back in gear and up to speed. I have recently "rediscovered" the Raspberry Pi stuff however... and purchased a Pi3B and a ZeroW to play around with CNCjs and Octopi a bit. All that stuff has really come a long way and my plan is to start to start giving the C-beam machine a bit more love and attention soon. Start a new thread if you want but please know that you are welcome to continue any discussion of this stuff here... it's a bit late to worry about how "eclectic" the thread has become. And quite a few folks seem to like it that way

Good work, Michael! As they say, "necessity is the mother of invention..."

Steve, you're right... it is really amazing what can be done with a 3d printer, CNC machine, and a little online shopping. You machine is proof... and I love what you are doing with the design. The tools and a consistent XY Home... and using the motor bell for the flywheel. I really hope this approach catches on. Looking back on the evolution of the needle cutter from a few posts above, the CPU fan version especially lent itself to using the motor bell's flat surface to mount the eccentric bearing and mounting post... it was a nice friction fit in the hole seen in the photo. I never had balance or vibration issues with that cutter... it was only running about 4000 rpm or so and was mounted on a heavy wooden CNC machine and I'm sure that had a lot to do with it. I cut "miles" of foam and a veritable fleet of fanfold foamies with that cutter, for my flying/fishing/golfing buddy and myself, before it finally gave up the ghost...

 

[Michael9865]

Z-Axis Issue
I have tightened/re-tightened and even added adhesive to the coupler that for the Stepper motor and the lead screw yet I am still getting this growling with no Z movement. It happens most often at the beginning of the cutting. Then it will perform the rest of the Z movements fine. The Z-axis feed rate is set to 50mm/min. Any recommendations?

 

[Michael9865]

Well, shoot... I guess my earlier posting got lost in the sudden forum changeover this morning

Fresh back from a 4-day fishing trip

David, How did the fishing go?

 

[dkj4linux]

Z-Axis Issue
I have tightened/re-tightened and even added adhesive to the coupler that for the Stepper motor and the lead screw yet I am still getting this growling with no Z movement. It happens most often at the beginning of the cutting. Then it will perform the rest of the Z movements fine. The Z-axis feed rate is set to 50mm/min. Any recommendations?

Michael, I must admit I can't tell what's going on there... I don't hear what I would call a "growl". It lifts, moves, and then lowers... the actual movement appears pretty normal to me. During the X move, however, I do hear a clicking sound... possibly the ribbed sheath around the motor and needle cutter cables is rubbing against something? It seems pretty taut.... and tightens further during the X move. Finally, to top things off... a clock chimes, or a timer sounds, when the cutter lowers? Does it do this for other gcode files as well, that move out to a different location to begin cutting?

The fishing was really great for 3 days... then, with heavy rain and thunderstorms forecast for the next day, the fish mysteriously stopped biting around midday. We were tired and the freezer was full... so we headed home, entirely satisfied with the trip.

-- David

 

[ironkane]

Z-Axis Issue
I have tightened/re-tightened and even added adhesive to the coupler that for the Stepper motor and the lead screw yet I am still getting this growling with no Z movement. It happens most often at the beginning of the cutting. Then it will perform the rest of the Z movements fine. The Z-axis feed rate is set to 50mm/min. Any recommendations?

I had a similar issue. I'm assuming you're using Ramps/Marlin? I don't know the settings for Ramps, but on my GRBL board it had to do with acceleration and holding power. This is probably in your configuration.h file. Z is trying to move too fast too soon. You have the correct steps/mm set for Z? 1/8 microstepping for Z?
Disconnect your stepper from your Z gantry. Test. Connect the stepper to one of the other axis and test. It will probably look like it's working. That will mean that it's configuration. I was fortunate enough to have support from my controllers vendor. I hope this helps.

 

[Michael9865]

Michael, I must admit I can't tell what's going on there... I don't hear what I would call a "growl". It lifts, moves, and then lowers... the actual movement appears pretty normal to me. During the X move, however, I do hear a clicking sound... possibly the ribbed sheath around the motor and needle cutter cables is rubbing against something? It seems pretty taut.... and tightens further during the X move. Finally, to top things off... a clock chimes, or a timer sounds, when the cutter lowers? Does it do this for other gcode files as well, that move out to a different location to begin cutting?

The fishing was really great for 3 days... then, with heavy rain and thunderstorms forecast for the next day, the fish mysteriously stopped biting around midday. We were tired and the freezer was full... so we headed home, entirely satisfied with the trip.

-- David

About the seven second point there is a noise just before the bell, it misses steps during the noise. I have not re-installed the cable support yet, so that is the cable movement issue. The bell dings because of the extremely short program. The rest of the program runs without a hitch, except for now the Z axis is not at the correct height any more. Sorry for any confusion.

**Issue Resolved.** I re-adjusted the stepper controller voltage back to .9vdc from .5vdc. Working good again. I don't know what made it change, but the Y and Z where still at .9vdc.

 

[grasskisser]

Hi - if you guys where just beginning with CNC needle cutting. Which design would you go for please. I am at the point of wanting to make one.
Have good engineering/cnc facilities.
Any advice appreciated.

 

[rockyboy]

I'd suggest either the MPCNC or the Lowrider, depending on what other uses you might have for the machine in the future

 

[dkj4linux]

Hi - if you guys where just beginning with CNC needle cutting. Which design would you go for please. I am at the point of wanting to make one.
Have good engineering/cnc facilities.
Any advice appreciated.

Grasskisser,

Assuming you are talking about the needle cutter itself, take a look at this post (http://forum.flitetest.com/index.ph...heets-with-a-needle.24251/page-98#post-395267), and throughout this lengthy thread, to see that there isn't any "standard" needle cutter configuration... motor, eccentric, needle, and primary guide are the basic elements of all successful cutter versions to date. Wood, metal, 3d-printed, and/or a combination of materials/methods... it's construction is really up to you and what you are comfortable working with. It is a very straight-forward DIY build but it must be adapted to your CNC machine and use requirements... with the tool mounting method to your CNC machine being one primary driver. Having "good engineering/cnc facilities", you should find it relatively easy to get something built and running that will meet your need.

I know this thread is long and specific information can be a bit difficult to find but, ultimately, the needle cutter's basic configuration and operation remains unchanged from the original versions shown early in the thread... KISS has reigned supreme. Significant improvements have indeed been made but largely they are subtle... requiring no additional moving parts. Some sort of "pre-guide" (bearings, sideboards, pins, wooden stacks, etc.) insures relatively straight-line motion of the needle as it passes through the primary guide (usually a MIG-welding tip or sport-ball inflation needle)... and reduces friction-heating in the guide that will adversely affect cutting and needle life. The distance from motor shaft to guide entry has been increased over the original to reduce the severity of needle flex and increase needle life. Some have found a "cotton-wad oiler/damper" further reduces friction in the primary guide and helps stabilize the needle.

Finally, in operation, finding a good ratio of cutter RPM and feed rate is imperative to getting good quality cuts in whatever material you are trying to cut. There will, of necessity, be a bit of trial and error on your part to find what works best for you. For example, I have found that when working with DTFB (with paper on), clean cuts are generally obtained when I insure 10-15 perforations per millimeter of cut.

Please provide information about your CNC and use requirements and we'll do our best to help you have success getting a cutter built in short order. This is a relatively simple and rewarding build but it's not without its frustrations.

Welcome to the party! -- David

 

[jhitesma]

So...I'm still looking to experiment with GRBL and using my machine more as a traditional CNC...but have hit a few setbacks.

1) The first day I used my pine64 in my office it worked perfectly. Plugged it in, it found the wifi automatically and connected and I was able to use it. But it stopped responding after a day and when I rebooted it it no longer connected to wifi. It only has HDMI output and I don't have any screens in my office that accept HDMI or any converters to go from HDMI to anything any of the screens out there can accept. So my only option is to work with it over the network...and when it doesn't connect to the network...that's....tricky But...I brought it into the house and plugged it in...and it connected just fine again. So it seems it's not happy about the wifi signal out in my shop - which isn't surprising since I know wifi out there is iffy. Looks like I need to step up my network a bit. I do have a wifi bridge out there but it only has one port and that's used by my computer. So I need to dig up an old hub or switch and then I can just hardwire the pine and not worry about network connectivity.

2) I started adding endstops to my machine and ran into two issues. The first is simple, the wires aren't long enough and I don't have any appropriate wire on hand to extend them with. Easy fix I just haven't had time to get any wire. The bigger issue is mechanical. My machine doesn't like to stay square when the steppers are powered off. I've been dealing with this by just pulling it square against physical stops before starting a job. But if I'm going to start using homing and endstops...that's not going to work well because the endstops get in the way of my physical stops. I was able to partly improve this as I noticed awhile back that one of my Y rollers has a bearing that never touches the rail. I tightened the cross bolt on that roller to snug it up and the bearings all make contact now and the machine stays more square. Not sure I 100% trust it yet though...need to do some more test cuts to see how it does. I suspect the real issue is a few issues i had with printing some of the Z parts and the real solution is still going to be reprinting the new 525 parts and rebuilding my machine which I've been putting off becuase of the 12 hours prints of the new Z parts.

3) My wife's schedule has been really bad lately and I've had no evening time to get out to my shop. And last weekend I had to completely replace the AC in our truck which ate up my whole saturday...then a vacuum line that controls the vents broke right inside the firewall so I got to spend all of Sunday pulling the dash off to track that down and repair it. Tons of fun...20 year old truck that has spent all of those years in the desert. The dash was so brittle just looking at it causes it to crack sometimes. So...yeah, big chunks of dash are now broken and cracked. So I've been spending what little time I do have for projects this week trying to repair it as best as possible with epoxy, fiberglass and some other tricks. Yuck.

So...I do still plan on trying the CNC shield and grbl on my machine...but it's going to be a few more weeks before I probably have any progress to share.

 

[ironkane]

Grasskisser,

MPCNC is a good choice. I own one, but it's currently propped up against the wall because I love my OpenBuilds way more. A MPCNC, without printing your own parts, will set you back $441. $155 of that is the printed parts. $286 for the hardware and electronics and sundry items.

A OpenBuilds Acro sized to cut DTFB will set you back $337.99, but it doesn't include the CNC controller. A Ramps 1.4 controller on Amazon will be less than $35. That'll bring it up to around $370. This doesn't include a Z gantry though. I took my 40" x 40" Acro and cut it down to 40" x 30" and used the cutoff pieces for the rails of my Z gantry. A gantry plate with the wheels, a 8mm Acme Lead Screw, Nut Block and another Nema 17 will set you back another $75. Bringing you to about $412. There's also a new piece of 1/4' acryllic $1.65 and I had to print out a couple of pieces to complete the gantry. At this point, I'm about $30 cheaper than the MPCNC. And there was some other sundry items like limit switches and various nuts and bolts. Still, the costs are so close as to be inconsequential.

The OpenBuilds is way smoother, quieter and more true than the MPCNC can be. Extruded aluminum V-Slot rails are stiff, straight and silky smooth. Electrical conduit isn't. It's manufactured to be sort of straight and it's hot dipped in zinc and you can visually see the variations. You have to sand them smooth and they're still loud as those metal bearings are rolling across those hollow tubes. The delrin wheels rolling across the V-Slot rails make no noise and all you hear is the stepper motors.

The MPCNC is a award winning design. Literally. I absolutely applaud Ted's achievement in winning the design contest. But it's not the most cost effective unless you 3d print your own parts and don't mind looser tolerances and the noise of metal rolling on metal.

I'll probably be up and running on my OpenBuilds this weekend. It doesn't look like my GRBL CNC Controllers PWM output is going to initialize my ESC for the needle cutter. I bought a PWM to PPM converter that I'll be testing out tonight or tomorrow. If that doesn't work, I'm just going to take a standard servo controller and incorporate it into my CNC controller setup. Everything else is done with the exception of setting up Homing. It's been a long time coming, but if i was to build another one, I could go from kit to completion in a day. Assembling the Acro frame by itself was only a few hours. The MPCNC was last winters project. Overall, I spent about the same amount of time as this years OpenBuilds project. Some different learning curves were involved. Both were great fun.

MPCNC = Good
OpenBuilds = Better. I know I'm fighting inertia here. But choices are good.

 

[ironkane]

So...I'm still looking to experiment with GRBL and using my machine more as a traditional CNC...but have hit a few setbacks.

3) My wife's schedule has been really bad lately and I've had no evening time to get out to my shop. And last weekend I had to completely replace the AC in our truck which ate up my whole saturday...then a vacuum line that controls the vents broke right inside the firewall so I got to spend all of Sunday pulling the dash off to track that down and repair it. Tons of fun...20 year old truck that has spent all of those years in the desert. The dash was so brittle just looking at it causes it to crack sometimes. So...yeah, big chunks of dash are now broken and cracked. So I've been spending what little time I do have for projects this week trying to repair it as best as possible with epoxy, fiberglass and some other tricks. Yuck.

So...I do still plan on trying the CNC shield and grbl on my machine...but it's going to be a few more weeks before I probably have any progress to share.

Jason,
Do you have a Dodge Ram circa 2001? I can't believe that they made the dash out of non-UV safe plastic!!!! I had to replace the entire top of my dash with a aftermarket ABS replacement. I never did get around to replacing the instrument bezel. But I get really good A/C flow without the vent grills.

 

[jhitesma]

Jason,
Do you have a Dodge Ram circa 2001? I can't believe that they made the dash out of non-UV safe plastic!!!! I had to replace the entire top of my dash with a aftermarket ABS replacement. I never did get around to replacing the instrument bezel. But I get really good A/C flow without the vent grills.

Close. 1998 Ram.



No chance of replacing these bits - they're way too brittle and shattered:


The bezel is the part I'm actually working on repairing. So far so good...basically using CA to rejoin the pieces then epoxy and fiberglass on the inside to reinforce it. It's not nearly as brittle as this top piece.

Around here it's VERY common to have carpeted dashes since even "UV Safe" plastics don't last long in our heat and sun - this truck is the first vehicle I've owned since moving here that didn't have one...we meant to get one but never quite got around to it. Will probably get one now just to hide how bad the top is