CNC-2116 - Up and running, sort of (2015-03-21)

[Yvan256]

Warning: this post is heavy on technical details, only has one photo and involves mathematics!

(insert "Get on with it!" clip here)

After I had installed everything (motor, threaded rod and stepper driver), I had problems with the torque... I knew that a surplus stepper motor that only cost four dollars wasn't going to deliver extreme torque and speed, but I was completely disappointed. The motor was missing steps when trying to move the X-axis without any force applied to the cutting tool!

Then I looked at my AVR code again. I was driving the motor in wave drive mode instead of full step drive. 

In full step drive, the torque is better and I'm pretty sure that once I apply dry wax on the threaded rod it's going to be better. Hopefully that metal-on-metal grinding noise will also go away. 

The motor is only 48 steps per rotation, but combined with the 1/4-20 threaded rod it means 960 steps per inch, or 26.4583333 microns. That translate to 0.0264583333 millimeter per step, compared to the 0.01 millimeter per step of my Roland MDX-3, or around 38% of the precision. That may seem low, but when you consider the cost of CNC64 vs the cost of the MDX-3 (even its cost when bought used on eBay), it's still amazing.

And if that's not precise enough, I just found out that putting vinyl tubing on an 8-32 threaded rod allows it to fit inside the fuel line motor coupling. That would mean 48 steps * 32 = 1536 steps per inch, 16.5364583 microns or 0.0165364583 millimeters, 60% as precise as the MDX-3. Of course, the higher the thread count, the slower the machine will be.

I could also "overvolt" the motor and limit the current, but then we get into costlier electronics. When you consider that in my setup, the cost for a stepper motor and a stepper driver is below 10$, it's hard to beat. But you also need to accept the limitations.

I'm still not sure if it's going to be enough for the Z-axis, I may have to go with the 8-32 rod for that. But the speed of the vertical axis is not much concern for me since my designs are mostly "2D".

[Yvan256]

Yesterday I cut two replacement panels for the machine. These new versions have holes for a T-nut and two bolts to hold it in place. I removed the "teeth" of the T-nuts with pliers and flattened the edges in a bench vise. These modifications allow the T-nuts to sit completely flat with the material. The small recessed edge of the middle hole is to compensate for the curved edge of the exterior of the T-nut.

Photos of the T-nuts in the new panels for the X-axis and the Z-axis. The Y-axis is lagging behind because I have not yet finished the design.

I do know that with simple T-nuts, I'm going to get backlash. Will it be small enough that I can ignore it? I'm not sure yet. From what I've read, the best way to test backlash is to cut a circle. I plan on doing a ballpoint pen holder so that I can do tests without cutting any material. It will be especially useful for testing printed milled circuit boards. My guess is that "cutting" a circle with a ballpoint pen will make it easier to check for backlash.

[Unstupid]

I do know that with simple T-nuts, I'm going to get backlash. Will it be small enough that I can ignore it? I'm not sure yet. From what I've read, the best way to test backlash is to cut a circle. I plan on doing a ballpoint pen holder so that I can do tests without cutting any material. It will be especially useful for testing printed milled circuit boards. My guess is that "cutting" a circle with a ballpoint pen will make it easier to check for backlash.

The best way to test is to CUT a circle not draw one.... you wont be subjecting your rig to any torque with a ball point pen.

[PL1]

I removed the "teeth" of the T-nuts with pliers and flattened the edges in a bench vise.

Why not get this type that use wire brads through the flange holes to prevent them from twisting?  Lowes carries them.




Scott

[Yvan256]

Why not get this type that use wire brads through the flange holes to prevent them from twisting?  Lowes carries them.



Scott

I did try to find these nuts locally, without any luck. That's why I went with hacked T-nuts instead.

Also, there's no Lowes in Québec.

[Yvan256]

The best way to test is to CUT a circle not draw one.... you wont be subjecting your rig to any torque with a ball point pen.

Indeed, but if it can't draw a circle with a ball point pen I expect it won't be able to cut one either. I wouldn't limit myself to drawing one, it would only be the first test. I also need an excuse to make a ball point pen attachment.

edit: I'm not sure how to merge my last two replies into a single one. 

[PL1]

there's no Lowes in Québec.

Amazon has them, too.   


Scott

[Unstupid]

http://www.widgetworksunlimited.com/  for the plotter pen... also felt > ball point! 

[Typefighter01]

Install two T-nuts either back to back or one on either side of your "panel" (one on either side would probably look best, but I can't tell from the pics if there is enough depth before they bottom out on each other). This way you can just turn the backlash out by turning them in different directions and locking them down with the two bolts. DIY anti-backlash nut. Nice going BTW

[Yvan256]

Amazon has them, too.   

Scott

Amazon Canada doesn't have the same huge catalog as Amazon USA, though I haven't checked for that kind of part in particular. After all, my Dremel router bits do come from there after all. I'll need to talk to my friend to see if he's ordering more stuff from Amazon soon. I don't feel like paying 15 dollars in shipping for 2 dollar parts.

http://www.widgetworksunlimited.com/  for the plotter pen... also felt > ball point!

Yikes, 40 dollars for a plotter pen... that's nearly half of the cost for CNC64 so far! I'm going with a "hacking-style" plotter pen... BIC ball point pen with DIY spring system if I can't find one with a built-in one. And by felt, do you mean something like a Sharpie?

Install two T-nuts either back to back or one on either side of your "panel". This way you can just turn the backlash out by turning them in different directions and locking them down with the two bolts. DIY anti-backlash nut. Nice going BTW

Thanks! And strangely enough that's exactly what I was thinking today!

However, I still plan on trying home-made acetal/delrin/HDPE/etc plastic nuts, using a slotted threaded bolt as a home-made tap. At the very least, I should try to find T-nuts or similar in brass instead of whatever those current T-nuts are made of, the friction is just too much for those low-power motors.

edit: I just did some tests with the Z-axis and I'm quite certain that without the friction from the T-nuts, they would be powerful enough at a lower speed.

[Yvan256]

The Z-axis was having a hard time, so in the meantime here's a video for the X-axis movement.

I'm not sure how to embed a video from Vimeo directly in my post, so here's the link:
http://vimeo.com/user17022509/cnc64-2013-03-12

[Yvan256]

Yesterday I was able to cut the four panels required for the new design of the Y-axis assembly of the machine. Even though the old design already had six panels cut, the design was getting too complex for no good reason.

I was also able to cut yet another replacement panel, this time the reason being that I had forgotten about the end stop microswitches. To make it a bit more arcade-related, I'm using D44 Cherry microswitches. I still need to replace a few other panels again to add the microswitch mounting holes, cut those 8mm rods and paint a few panels, but otherwise the project is nearing completion. Then I'm back to my CNC256 project so that finally after that one I can get back to my arcade-related builds. 

Also, as you can see, the new panel with "CNC64" and the top two panels of the Y-axis assembly have rounded corners but unlike all the previous panels with rounded corners, this time it's one of the new function of my "Dirty Easy CNC" which made them for me. I've made a function that can output different radiuses for each four corners. I just wish I hadn't lost nearly two hours because PHP's sin and cos functions take radians instead of degrees as input... 

[Yvan256]

Not much of an update for now. The two new top panels are cut, painted and installed, with their Cherry microswitch. The machine now has both home and end stop switches on its X-axis. I've also painted and assembled the four panels of the Y-axis assembly.

I also finally ordered the router bit to be able to cut the T-slots (16J60.72) into the spoilboard that will go on top of the Y-axis assembly, along with a high-speed steel router bit (86J01.01) so that I can try cutting aluminium on the MDX-3. Yes, that small machine takes 1/4" router bits... crazy, right?

The reason I'm going with slots cut directly into the spoilboard is because it makes the whole thing easier and lighter and there's no danger if the router bit ever hits the slots, unlike aluminium rail slots. It also means I can cut many more spoilboard with T-slots, for example a new spoilboard for the MDX-3, the first CNC64, the CNC64 clone, CNC256, etc. With aluminium rails you need to buy rails every time you make something new.

I also ordered T-slot nuts and bolts to use with the rails of all the machines and a bushing adapter so that I can use Dremel bits on the MDX-3. I smell milled circuit boards in the near future.

The last photo is something completely off-topic, as if posting the build of a CNC machine on an arcade forum wasn't already off-topic enough (hey, the home and end stop switches are arcade-grade Cherry microswitches, what more do you want?). I was getting tired of the fact that the batteries in my calliper box shuffled around so I cut a little PVC holder for them. 

[Yvan256]

I received my parts from Lee Valley and cut two T-slot beds. I also made a new Y-axis motor mount plate since my small, used NEMA17 motors seem to be a bit stronger than the bigger "tin can" stepper motors.

If you like MDF dust, you really should get one of those T-slot cutting bit! 

In the next few days I plan to cut a new MDF bed with T-slots for my Roland MDX-3 as well.

I just thought about cutting T-slots into the bed for CNC256... that's going to make a boatload of dust. 

[Yvan256]

Funny how things turned out. I wanted to complete the Y-axis assembly before going any further, to test with the step motors and all... and it's practically the last thing to get finished.

Yesterday I cut a new replacement side panel for my new motor mount plate (that's why it's missing in the first two photos), one motor mount plate and also cut six printer/scanner rods. Cutting those rods is hard, it's eaten almost a quarter of a Dremel cutting wheel to cut six ends! I've also upgraded the Roland MDX-3 to a new T-slot bed. It's so much easier to clamp boards down now!   

Here's a few photos to go with this update. The first two are the Y-axis assembly without and with its T-slot board.

The third photo is a PVC mounting panel for my used NEMA17 motors and room for the stepper driver board. These motors don't have threads so the 3mm bolts need to go all the way through the motors and I can't find bolts long enough locally to go through both the motor and the MDF. The wires of the motors are also very short so I'd rather have the stepper driver board right next to them.

The space for the drivers is huge because I made the schematic for 2mm traces, just to be sure I can't mess them up while milling them and because I'm still coding everything by hand, so square uniform traces are easier to do. The 4th image is a Sketchup screen capture of that board. Top drawing is the board viewed from the top with most of the components in place, bottom drawing is the bottom of the board with the traces. I could probably have gone with smaller traces in some areas, but I made a function in PHP to have grid-aligned holes and traces so that's the result.

[Yvan256]

I was planning on using the Roland MDX-3 to mill the circuit board, however the 1/8-to-1/4 adapter just doesn't work with the press-fit spindle of the MDX and I can't cut circuit traces and drill IC holes with a 1/8" router bit...

So I had to turn, once again, to laser-printed circuit boards. Here's a photo of my fifth attempt, the only one successful after four failures.

I read a good tip on YouTube:
1. heat up the copper clad board (CCB)
2. instead of going table, CCB, paper, iron like most people do, go table, paper, CCB, iron (with the copper facing down on the paper with the toner-printed circuit, of course)
3. heat up CCB again, pressing everywhere
4. reverse, iron evenly all over the circuit
5. soak in hot water

This reverse process made the paper remove itself completely after a few minutes, and zero toner was left on it, it all transferred to the copper! 

I was a bit rough on the traces afterward, that's why there's a small bit missing in a middle trace.

edit: second photo shows the PCB with the traces etched and cleaned, third photo is the PCB with all the components minus the power and signals connectors and the jumper wires. I still need to cut the PCB outline and solder the components, otherwise it's complete.

[rablack97]

I etch boards myself....

I'm confused on the heat up CCB......

Heat it up how.....

Do you heat it up then iron?

Heat it up again? How?

Then when you say reverse, do you mean flip it over and iron the paper side?


If you use good printer paper and have a good laser printer, the toner will come off the paper no issues...

The biggest mistake folks make in this method is either the iron isn't hot enough or they are too impatient and dont iron long enough.

One sign i use is if i can see the traces through the photo paper when ironing, or the paper starts turning a little black.

Then i soak in cold water, and the paper peels right off.

Next time use a little soap and light scouring pad, to remove the rest of the paper off, rub lightly and be patient it will come off....

[Yvan256]

I etch boards myself.... I'm confused on the heat up CCB...... Heat it up how..... Do you heat it up then iron? Heat it up again? How? Then when you say reverse, do you mean flip it over and iron the paper side?

The usual method is to put the CCB on the table (copper face up) and put the photo paper (face down) on it and then iron the whole thing out.

The method I picked up from a comment on YouTube said to put the photo paper (face up) on the table and then drop the heated CCB (copper face down) on it, heat up a bit again on the non-copper side, then flip over and just iron out as usual. I've found that it leads to better and faster results.  I still have two boards to do, so maybe I'll try this method again and the non-reverse method, keeping all other steps as similar as possible and compare the results.

If you use good printer paper and have a good laser printer, the toner will come off the paper no issues...

The biggest mistake folks make in this method is either the iron isn't hot enough or they are too impatient and dont iron long enough.

One sign i use is if i can see the traces through the photo paper when ironing, or the paper starts turning a little black.

Then i soak in cold water, and the paper peels right off.

Next time use a little soap and light scouring pad, to remove the rest of the paper off, rub lightly and be patient it will come off....

I'm using Epson inkjet glossy photo paper (ran out of Staples inkjet photo paper), but my fifth attempt gave good results. My iron is at maximum, maybe I was too impatient on my first four attempts.

Thanks for the tip about watching the traces through the paper while ironing and for cleaning the board. Maybe my next two boards won't have damaged traces.

Do you have a trick for cutting out the boards? Scoring with a knife takes forever. 

[rablack97]

For cutting the boards, you can use these...Once the copper is gone, the material is easy to cut. Although it also depend on the material your core is made out of.  Some cut easier than most, i've had no issues with the paper cutter though....



Or my favorite if you can find one cheap is this....



I'm looking at one of these in the future though....step it up a notch...



I'm still not following, the heat it up part....How are you heating it up before ironing....

Honestly, patience is the key, you can flip it upside sideways....etc doesn't matter.  Ironing from the underside isnt really transferring heat any better, just seems like wasted energy.

This is what i do..

Tape photo paper to copper
Place copper on thin towel, to preserve table (Mrs. kills you if you dont)
Place iron directly on photo paper, hold for about 30 secs pressing down hard (this is the key pressing down hard and even)
Never lift the iron off the board, and use the tip to hit all of the edges
Stop every 30 seconds or so and press down hard....
When the paper starts turning black or you start really seeing the outlines of the traces then you should be good


Also, get you some liquid tin.....it tins your traces and protects them, and it makes for easier soldering.....

[Yvan256]

I have similar cutting scissors but it just cracks the edge of the board while cutting, but I do have a slicing paper cutter, so I'll try that!

A tile cutter would be nice but as soon as CNC64 is completed and working, I'll be making the boards with it. Holes with drill bits, traces with specialized V-carve bits and board outline with a "chip breaker" bit. I've already tried the chip breaker bit on a random piece of PCB and the result is extremely clean, almost like a commercial board. Being controlled by a CNC means complex board shapes will also be possible.

Thanks again for the tips, I'll see if I can find liquid tin.

[rablack97]

I have similar cutting scissors but it just cracks the edge of the board while cutting, but I do have a slicing paper cutter, so I'll try that!

Yep that's the material i'm referring too that's more gummy...There is a material that cuts much easier....

The paper cutter should help you out...or if you have a band saw, i've had luck with those too....

[Yvan256]

I'm still not following, the heat it up part....How are you heating it up before ironing....

Sorry I forgot to answer that question. It's just about heating up the copper board with the iron before applying the photo paper to it.

[Yvan256]

First off... wow, over ten thousand views! 

You guys have even more patience than me!   


Well, back to the topic I guess... When you use surplus parts, you don't really get to choose much of anything as far as specifications are concerned.

My NEMA17 motors don't have threaded holes, so I had to figure out a way to mount them and the only local store which had bolts to fit the mounting holes didn't even have bolts that were long enough to go through the motor and the MDF.

About a month ago, the local sign store gave me some thinner expanded PVC panels and it was the perfect thickness for the length of the bolts, so here is two of the motors installed on their mounting plate, bolted to the CNC machine. I'm only missing couplers and I have two axes ready to go! Well, except that I need to make more driver boards.

Speaking of driver boards, the last photo is of my custom stepper driver board which I still need to cut properly. But guess what? I made two mistakes in the design. I forgot one trace for the ground of the ATtiny84 when powered from the power connector and I forgot a ground line for the step/direction communication pins. The first mistake would be easy to patch with a simple wire underneath the board but the other mistake would require a weird split connector but I do have a ground pin on the ISP header for the ATtiny84...

Considering the cost (around 8$CAD in parts) and the trouble of making the board versus buying a stepper driver on eBay, I'm not sure even the first CNC64 clone will be using my custom boards. The drivers on eBay have gotten extremely cheap, there's a lot to choose from at around 6~12$ so it's not even double the price of a home-made solution.

Of course the cheaper drivers are weaker than my IRLZ14, however those small NEMA17 motors aren't exactly powerful either. Even the all-in-one boards (from parallel port to stepper drivers) are in the 40~50$CAD range now. With the popularity of 3D printers, everything seems to have come down in price over the last few years.

[Yvan256]

I just finished the second stepper driver. The board is much cleaner, there's no missing traces, all connections are there, etc.

Nothing exciting for now, but once the third stepper driver is complete, I'll be able to do some tests with something like TurboCNC!

[Yvan256]

I wrote the code for the ATtiny84 used in my low-cost stepper driver. Nothing fancy, it's a full-step driver, no micro-stepping or current limitation here. The code is only 220 bytes, however, so even an ATtiny24 would only be 11% full. I'm using ATtiny84's because that's what I have on hand. They're socketed, though, so I'll be able to replace them with ATtiny24's the next time I order parts.

I'll be posting the schematic, a PDF for toner-transfer (single side PCB with only 6 wire jumpers on the top), parts list, source code and compiled code in the next few days.

In the meantime, it's fun to finally see more than one motor turn, I have an ATmega88 driving two motors for testing purposes. The next step will be a pre-programmed part (a CNC64 part, that is) and the next step after that, probably TurboCNC talking to those stepper drivers.

edit: forget that, the prices on eBay are so low right now that you can almost buy two L298N driver boards already assembled for the cost of one of my own driver. 

[Yvan256]

I'm still having problems with the Z-axis. There's too much friction on the threaded rod and the whole thing may be too heavy for the little surplus stepper motor.

The X and Y axis, however, seem to work fine even with the fuel line couplers holding in place without anything but friction.

So I re-traced the ATtiny24 stepper driver board to only have square lines everywhere and I hand-coded the paths required in the ATmega88. But I forgot to mirror the circuit before doing all of this. I'm glad I tested on a white piece of masonite first!

There's a few problems aside from the mirror image. My cutting bit is kind of big to cut circuits, some traces didn't cut "all the way through" because the masonite is probably not flat enough, a corner simply teared off the surface and I calculated everything for 18 turns per inch instead of 20. The weird-looking rectangle at the upper left is when I thought my stepper motors were 48~50 steps per rotation, turns out they're 200!

But it's still a nice first cut anyway in my opinion! 

[Yvan256]

Here's my third attempt at cutting the circuit board for the ATtiny24 stepper driver. The second attempt was the same exact cut but in a white hardboard.

The copper board is warped a bit on the edge, which is why the leftmost trace isn't cut all the way through. I'll try double-sided tape for the next cut instead of holding it in place with bolts and washers.

Because my Z-axis isn't done yet, I have to cut traces by going in a single line, so the bit often has to go backward in traces already cut. You can clearly see the backlash on some of the traces (look at the front of the filled "P" at the upper right), I guess I'll have to make those delrin nuts after all. 

If it had been a CNC64 part cut in MDF, I probably would never have noticed the backlash.

edit: my double-sided tape sucks, it can't hold the copper board to keep it flat.
edit2: nope, double-sided tape is fine after all, I was just being a bit stupid earlier...
edit3: double-sided is more than fine, it's actually extremely hard to remove from the polycarbonate plate after the CNC is done cutting.

[Yvan256]

So, it's been a month since my last update and some people might be wondering why.

First, as a follow-up on my last few posts about milling circuit boards. Last week, I've read about OSHPark on SparkFun. And with the pricing of OSH Park including free shipping to Canada,  I don't see myself ever doing another PCB/MCB ever again unless I absolutely need a board as quickly as possible. Even then, I'll simply use the laser-printed sheet+ironing solution. I've read that a solution of regular table salt, oxygen peroxide and vinegar can be used to dissolve the copper so I'm not stressed about finding ferric chloride locally either.

Secondly, and that's the biggest problem, is that the spindle motor on my MDX-3 was getting too slow and could barely cut anything anymore. The prospect of having to pay over 80$ to fix a 10$ motor wasn't at all appealing and I always hated the "ratcheting motorcycle" noise the motor was doing because of the way it was using friction on the spindle to make it turn.

Long story short: I've fixed and upgraded the spindle motor myself. The funniest part is how I did it.

The result sure isn't pretty, but I've fixed it with:
- one bolt
- part of a metal plate from an old HP printer
- a "12VDC PCB drill motor" from eBay (under 4$CAD, free shipping)
- three LEGO parts*! 

* Yellow Band
* small pulley
* Cut-up yellow plastic tubing to fit the pulley on the motor shaft (can't find the part number)

The best part of that story is the MDX-3 spindle is now belt-driven (a bit more quiet than before) and seems to be about two or three times as powerful than before, if not more. And it's not because it's a 12VDC motor vs the original 5VDC motor because I need to power it with only 5VDC too otherwise it's way too fast and noisy!

And if the need ever arise, I can replace the spindle motor for about 3$ and I already have a spare one in stock.

Attached are photos of the hilarious fix, which includes a piece of expanded PCV I used to hold the spindle in place to replace the original little metal plate. I'm sure the Roland company would not be proud. Who knows, maybe they'll be embarrassed enough to send me a free MDX-15 (wink, wink)!

edit: as a test run, the MDX-3 is cutting a single 24mm hole in 10mm MDF as I'm writing this. The noise level is much, much lower than before.

edit2: the 24mm hole in MDF was successful, so now it's cutting hard plastic for the first time. The same 24mm hole, in a CD-R.

[Typefighter01]

The best part of that story is the MDX-3 spindle is now belt-driven (a bit more quiet than before) and seems to be about two or three times as powerful than before, if not more. And it's not because it's a 12VDC motor vs the original 5VDC motor because I need to power it with only 5VDC too otherwise it's way too fast and noisy!

Looks like you created some torque mutiplication with your pulley diameters...nice upgrade

[Yvan256]

I tried to cut a new panel for CNC64, but it seems my "repair" didn't work as well as I thought. 

This situation is a bit frustrating, because MDX-3 has a working X/Y/Z table but no spindle and CNC64 has a perfectly good spindle (the Black & Decker RTX) but is still missing a working Z axis.

edit: After careful verification it seems the LEGO silicon band isn't up to the task of transmitting the power to the spindle. I've hacked the original spindle motor assembly back into place.

[Yvan256]

I've fixed the MDX-3 (again) and cut the first two replacement panels for CNC64. The threaded rod would give amazing precision but there's too many drawbacks: threaded rod/nut friction, backlash and slow speed.

So I've decided to switch to a belt drive system. After all that's what the MDX-3 uses and it's cut quite a number of MDF panels so far. A while back I went to the local recycling centre and got two very long MXL belts for free. I got more than enough for both the X and Y axis. My surplus motors already have MXL pulleys on them, so it's a perfect match.

One of the upshot of switching to a belt drive for X and Y is that it will now be fast enough for other applications. The Z axis is designed so that I can attach various things to it, the first one being the Black and Decker RTX and the second would be a 3D printer extruder. I'll probably try with a glue gun extruder first just to keep the cost down and to try an automated "rotating barrel" system for auto-loading the glue sticks.

Here's some photos of the new panels for the belt drive with another NEMA17 motor and a S2M belt, I'll be using my old beige/black ones with the larger MXL belts for CNC64. I just need to find longer 3mm bolts to attach the motors to these new panels.

[Yvan256]

The MDX-3's spindle is no more, my hack didn't hold. I'll try to put back the belt back in place but it's a mess for the mounting holes right now. It would almost be easier to build a brand new Z-axis platform.

On the bright side, the Z-axis of CNC64 is now working if I keep the speed extremely slow. Not much of a problem for the Z-axis, in my opinion.

I still need to make those acetal/delrin/HDPE nuts, I may have a little time this week so stay tuned.

[Yvan256]

Since my MDX-3 can't cut new parts to convert CNC64 to belt drive, I have to make it work with my 1/4-20 threaded rods.

So I spent the last two hours or so cutting thin slices of yellow delrin and doing threads in them. Strangely enough, the best result I got was drilling 1/4" holes to make 1/4-20 threads otherwise there was too much friction and I was afraid my little NEMA17 motors wouldn't be up to the task. I still need to cut them into nice rectangles and drill holes to attach them to the MDF panels.

The friction is so low, I'll probably be able to speed up my Z-axis by at least 25% if not more.

edit: nope, 1/4" holes wasn't a good idea. I stripped the threads quite easily just trying to push it manually. Good thing I didn't waste time trying to install them on the machine. It looks like it's going to be nylon nuts for the time being, unless I can repair the MDX-3 to finish cutting the new panels for the belt drive.

[Yvan256]

The MDX-3 has been repaired once more and is back at work cutting parts for CNC64. Threaded rods are too much trouble for my low-power motors, I'm definitely switching to belt drive, including the Z-axis if I can.   

Sorry, no photo for now.

I think I'm going to do a micro-cabinet that can fit in the MDX-3 cutting area, getting tired of posting about non-arcade projects. 

edit: the MDX-3 has cut four small parts and one medium part. I'm calling the repair a success.

[Yvan256]

I've been cutting a second copy of CNC64 for a friend, in exchange for a stepper motor driver controller board.

We're still waiting for delivery but it does open up the option of going with threaded rods right now with full/half stepping and upgrade to belts later with 1/16 micro-stepping and a few new CNC64 panels. It will also drive the steppers in bipolar mode, which makes them stronger than unipolar.

And since we're going to need remotes for the first threaded rod versions, I've been busy cutting panels for my MVS-style CNC remote. It's designed to use the popular Grayhill 04A-B01 to control the X and Y axis. I've even planned for a tiny 5x7 dots LED display in the "credits" area to be able to display either two digits or scrolling text. A 5x7 dots display on its side becomes 7x5, which is enough for two digits with a 3x5 font and will also allow "smooth" text scrolling. I used the control panel of MVS-99-6 as a starting point, that's why there is three white buttons.

The usual red, yellow, green, blue, player start, main menu and pause game buttons will be replaced with CNC remote functions (Z up, Z down, panic stop, etc). I'm also used to the tiny control panel of my MDX-3 so I'm probably going to copy some functions from it (i.e. start position and view position).

[Typefighter01]

Loving the MVS-style remote...too cool!!!!

[Yvan256]

Had to cut the back and front panels again because I forgot the side tabs the first time around. 

The MDX-3 is busy cutting the top panel, which is also the last one. I'm leaving the bottom open to have access to the buttons, etc. With no bottom I'll be able to glue everything together with carpenter's glue, no holes or bolts to ruin the look.

But it's going to take a while to cut that panel, with all those holes and pockets.

edit: it took 1 hour and 30 minutes to cut all the holes and it's probably going to take another hour or so to cut the outline of the panel.

[Yvan256]

It's done! All I need to do now is to round up the front edge, order red and black vinyl, try to find 3/8" black T-molding, order a printed vinyl overlay for the top, order the joystick and the buttons, make a small board with a microcontroller to emulate a USB keyboard...

Ok, it's not really "done" yet. But at least I'm done cutting panels for this mini-project.   

The first photo shows the little joystick retainer panel, the other two shows the controller with the 5x7 LED display. I'm glad I added 0.25mm padding all around otherwise it would not have fit in the hole.

edit: added a 4th photo with the edge of the top panel rounded at the front.

[Typefighter01]

Your remote has to be "done" now, no ?

What microcontroller are you using for the usb keyboard emulation?

[Yvan256]

Your remote has to be "done" now, no ?

What microcontroller are you using for the usb keyboard emulation?

I don't have that tiny joystick and I don't want to pay 8$ shipping for the joystick alone, so the remote is on hold for now. I also don't have small buttons for 10mm holes, the best "arcade-looking" buttons I can find on eBay (in white, red, yellow, green and blue) are 12mm, so I might need to cut the remote again anyway. I can make it maybe 10-20% bigger than it is right now.

In other news, I'm building another CNC64 for a friend and in exchange he's ordering some parts in double, one kit for him and one kit for me. That kit includes a newer model of those popular Chinese 3-axis stepper driver, the TB6560-3V2. I have to say, I'm really impressed for the price which was about 55$CAD each, shipped. It's a new version with big ceramic resistors, I had zero problems using it so far, I highly recommend it. Each axis can be setup for 1/1, 1/2, 1/8 or 1/16 micro-stepping. I'll be ordering a second board for my bigger CNC256 machine.

I've been testing my 103H5208 stepper motors that I got from the recycling place and I just can't believe how strong these tiny motors can be. If you tried to hold their metal pulleys while it's spinning you'd probably rip the flesh from your fingers. They're scary strong.

And since a slow CNC is a boring CNC, and since those 103H5208 motors already have tiny S2M metal pulleys on them, I decided to go with a belt drive after all. I should have the Y axis finished before friday. And because the motors are really strong, I've also decided to go with a belt-driven Z-axis as well. Cutting 3D plaques will be lightning-fast or at least as fast as the Black & Decker RTX can cut them. It sure won't be the CNC itself that will be too slow.

For now I'll be testing with MXL belts that I got from old printers and scanners, because my S2M belts are still on their way from China.

Enough with the boring life story, here's some photos! As you can see, the way I mount the motor for a belt drive got reinforced from the last time I posted a photo of that setup.

edit: I added an image from the eBay auction comparing the older vs newer driver board.