Great result, bravo!
30 minutes seems a bit long for such a small part, what parameters did you use?
About your problems of machine stopping, instead of using repetier, I suggest you to use the SD card directly. Using the SD card will rule out any computer related issues.
Thanks, and I will keep that in mind. Normally on fusion 360’s CAM, I do a contour finish pass where under “Stock to Leave”, I put a negative value which actually does oversize on purpose. It’s a cnc router so tolerances are pretty loose. I am getting within .1mm which is great for my purposes. Very true about oversizing, it’s so easy to file fit vs trying to…idk shim the fit with something else.
SD card sounds like a good idea. 30 minutes is mostly due to the fact that my toolpaths are trochoidal. The advantage to this is that I can do really deep cuts without the chips getting burried in a 3mm wide slot. The disadvantage is that I actually have to remove more material than “necessary” to create the cutout geometry.
I used
7% trochoidal step
70% trochoidal width
3.2mm DOC
900mm/m (This can be faster but I if I go faster, I get weird interruptions, probably the arduino usb bottleneck) Son of a diddly!
Really need an idea for a cheap air blast. I literally wouldn’t care how long the toolpath is as long as I don’t have to watch it with a vacuum. To think most of my previous 3d prints took WAY longer than 30 minutes, this seems fine. I care more about repeatability since I want to do a production run of at least 20 of these. Knowing I can hit the green button then do other things would be awesome.
Well, that is still quite an aggressive setting, I’m impressed.
70% width is quite a lot, but if it works fine, then go for it. During my tests I’ve set it up to 50% or less.
Do you have a workshop air compressor? You could easily hook it up to the cnc, then just add a simple valve to set up the air flow, and a flexible tube to get it where you need. You could even add a solenoid valve to start/stop it whenever you want.
If you don’t have an air compressor, well… buy one! It is one of the most useful tools around the shop, a must have! Plus it doesn’t cost too much, a small 30 liters one should be enough.
About the speed, what you can do is to lower the microstep setting. I suppose you are using the 1/32 step mode, so try 1/16 or even 1/8. That’s what I use on my 3040, it gives much more room for speed and doesn’t seem to have an impact on accuracy. Could worth a try.
That and a drill press are clearly missing from my makeshift dumpy garage. I don’t really have any income…so this may get kind of ghetto rigged. If I could still print something I would try to get like 4 12v high static pressure(and noise) fans and then combine their air into a single stream.
Doubt it will have enough pressure though. Just wondering if buying all these “upgrades” is worth it.
I also owe some money in ebay fees…don’t tell them I was here! 
Good idea on 1/16th stepping, guess I have to change my jumpers. If there really is no change in accuracy I don’t see why not.
I am running outa power in the garage here. Not that many outlets, and I have an electric car charger that’s 1400W on the same breaker.
I think I am going to go with this http://www.ebay.com/itm/Mist-Coolant-Lubrication-Spray-System-Unit-for-CNC-Lathe-Metal-Milling-Machine-/311768128985?hash=item4896d41dd9:g:9lMAAOSwf-VWYj6x
and http://www.homedepot.com/p/Husky-4-Gal-Portable-Electric-Powered-Air-Compressor-BS1004W/206480997
Seems like enough air to me, I really am not dishing out the next satellite to go to the moon. The mister is made for coolant but my guess is it doesn’t really need it. I just like how it has the line already there and has a valve.
You can get a lot of tools used on CL, too. I didn’t have luck with a compressor, but I bought my drill press on CL and I got a bargain. Tools that are designed for people working 40 hours/week won’t get worn out by weekend warriors, usually. And a lot of tool tech hasn’t changed much in the last 20 years.
Funny you mention that, cause I was just looking. For bigger stuff that is usually more expensive online (shipping cost), I find letgo to be good. Craigslist is good too but there’s all these newer options too like wallapop and offerup. Found a compressor for $40, may take a stab at it.
Maybe that’s why I’ve had trouble with Craigslist last time I tried to sell something…
Playing around with aluminum again.
https://goo.gl/photos/GEF1Pr4og7VEd7rb7
Drop down to the last four rows of pictures. I shortened the mpcnc back to my first dimensions. Have about 510 by 470mm of cutting area. After surfacing the spoil board I tried cutting some 2" aluminum bar. Didn’t work out so well. So I attached a second piece of mdf on top of the first piece, and attached a half inch piece of plywood to that. Then I did the masking tape and superglue method of attaching the aluminum to the plywood. Much better results! End goal is to mill out some name plates for my ladders at work.
Hate to just barge in on the answer but it looks like conventional. Climb almost always works better, the only downside is your bits can grab into the material and break your bit if you don’t have things really perfectly aligned. I’ve had it happen 
Little update, I have been doing not as many cuts recently, selling junk on ebay to buy the new air blast system. I wish I could go with a mister with some coolant, but my bed being particle board, aka a sponge, I would like to keep it dry. Picture is one of the motor mounts, before the width of the cut exceeded the stock and hell broke lose. My fault entirely, need more stock asap! Buying stock online bugs me knowing that I am paying an extra 35% just to ship it to me.
Squared everything all over again and my results are coming out fantastic. Once I get the air blast, I have full confidence in the mpcnc. As of now I have to follow the bit at all times with the shop vac or the chips build up in the slots really quick. It’s kind of cool, the chips form a fuzzy texture in a pile. They’re really nice chips though, like a small version of the ones you see in those youtube machining compilations.
To anyone else trying aluminum, always CLIMB mill! On the finish and on roughing. Conventional isn’t better at doing anything. The only time it doesn’t matter is during slotting.
Finished setting up the air blast today, maybe needs a little cable management. I went with a Husky 4gal from Home Depot. 3.7SCFM @ 40psi. Everything used was like a 30 minute drive. Plus no warranty.
The air nozzle I got is sort of junk, but for $8 I wasen’t expecting much. The air leaks through seams in the flexible portion of the hose, which wastes pressure. It is made for coolant to be run through it as well. Might run coolant one day but=that is a little overkill for now. I ran the air at about 40psi at a constant pressure, all in all it works well and the chips go flying all over the place like anticipated.
Do you have a site for your kits yet?
You can pick up my kits at https://shop.v1engineering.com/. We’re having a sale on cracked rollers. Order now and get an air nozzle that doesn’t leak half the air before it gets to your end mill.
New video, guess a little better quality than the old one. Cutting the 3/8" tall part I put above. Everything came out nice except for a tiny bit of chatter at specific points in the finish. All in all a good run, I think I have it dialed in! Now I need to run it 8 hours a day.
5mm DOC, 550mm/s @ 11% stepover for the pocket. 8% step length, 50% width, 800mm/s for trochoidal. Total part time was around 17 minutes.
Careful with those speeds, you are limited to 120mm/s XandY before steps get skipped, you can put in those numbers because the acceleration is limiting you because of the small travel. If you really want to go faster either increase the acceleration and jerk numbers in the firmware, and/or get larger pulleys.
I was asking about a site because a friend of mine is asking for suggestion on electric skateboards.
Oh sorry, thought you were just joking. Once I get a few of these cut I will list them on a forum, ebay, and maybe amazon but I don’t know for sure. I have my design all tested for the mount, just need some more 1/4" aluminum and I am good to go for prototyping. All it will be is the mount, a 608rs idler system, and the timing belt. Want to verify it works before I buy hundreds/thousands of screws, I am sure you know the feeling.
For a LOT of information I would lead him towards https://www.electric-skateboard.builders/. That is by far the biggest electric skateboard/longboard with a lot of beginners as well as advanced user info.
Dang what a fluke, I mean’t to say not mm/m not mm/s. My brain is still calculating for 3d printing. Let me go change all of those, you must think I am crazy!
Aaaanooother update. To anyone trying aluminum, seriously get a quality air blast. Without it you are at such a disadvantage, the whole process of cutting it will just not workout nearly as good, that is if you can even finish a cut without the end mill gumming up.
Turns out the hose and nozzle I was using was garbage! The kind I used to have that was a china import http://www.ebay.com/itm/Mist-Coolant-Lubrication-Spray-System-Unit-for-CNC-Lathe-Metal-Milling-Machine-/311768128985?hash=item4896d41dd9:g:9lMAAOSwf-VWYj6x
Not good at all. I still use the block and valve though. I recently upgraded for actual Loc-Line, made in the USA. Wow, what a difference. For $10 this thing barely leaks any air out and has a variety of nozzle choices. Highly recommended. Now my air comes out at 40psi instead of 25, and it made all the difference. The chips evacuate so good, even at 30k rpm I am getting minimal chip recutting.
It’s just so good 
