3 Axis CNC router

[JoeHarris]

A lot! I think the build will be the around 1500 to 2k? But to be honest I've kind of lost track! The biggest cost so far by miles is all the tools I have bought for the project. I keep realising I need another bit of equipment. From drill bits to taps and tap wrenches, centre punches, transfer punches, counterbores, a router, drill press, cut off saw, band saw, lathe, welder, callipers, dial indicator, computer, software etc etc the list goes on - so who knows. What I do know is I've learnt a huge amount and loved the experience so far... Look forward to seeing your build.

[JoeHarris]

on the subject of buying stuff my new m12 counterbore has arrived. Time to finish the gantry.

[njhussey]

I love the sight of shiny Aluminium.....really looking forward to seeing this move Joe

[routercnc]

Fabulous job Joe !

Even more so that you are making it by 'hand' without another cnc machine to help cut bits. Keep ticking away at it and before you know it you'll will be rewarded with a really solid machine.

[trigus]

Hello,

I'm very exiting your cnc design. Maybe you have video how cnc works? maybe can get drawings from you?

[JoeHarris]

Hello,

I'm very exiting your cnc design. Maybe you have video how cnc works? maybe can get drawings from you?

Hello, whilst I'm not at all opposed to sharing, in my experience the design process is essential if you want to understand what you are building and why. I would encourage you to read a lot on this site and others then get drawing!

[JoeHarris]

I had decided to go with slaved motors but I really want to use a CSMIO/IP-M Motion Controller and they don't like slaved motors. Early on I had toyed with a belt drive and after reading posts on biketrialdave's build log I'm heading back that way I think. The belt will need to be made as it is over the size limit for standard belts but the cost of a custom one does not seem extortionate! The basic idea is as the image above... which would not require much modification from the existing setup. As usual, any comments are gratefully received!

[routercnc]

I had decided to go with slaved motors but I really want to use a CSMIO/IP-M Motion Controller and they don't like slaved motors. Early on I had toyed with a belt drive and after reading posts on biketrialdave's build log I'm heading back that way I think. The belt will need to be made as it is over the size limit for standard belts but the cost of a custom one does not seem extortionate! The basic idea is as the image above... which would not require much modification from the existing setup. As usual, any comments are gratefully received!

Hi Joe,
I wonder if that long unsupported run of belt would flap and vibrate around. Do you think it would be in perfect syncrony on each ballscrew? Also, a single motor would need to be more powerful than 2 singles.

On my new machine (not CSMIO) I am going with 2 motors and 2 short belts, then one long slave belt between them which mostly does nothing unless there is a problem. Would CSMIO let you feed step/dir signals into 2 drives? Is that acceptable? I know you can't 'slave' home in the traditional sense with that suggestion, but with a link belt you wouldn't have to.

[JoeHarris]

I was going to up the motor to a nema 34 12nm beast. This is a similar size belt to Dean's first machine I think? He had an idler part way along not at one end. If I get flapping I could add one in the same way. I understood that the ip-m just did not allow proper slaving...

[JoeHarris]

Hi Joe,

Sorry not replyed to some of your previous post's where you asked me directly, I've had eye trouble so time on computer has been limited hence me not being around much.!

Others have answered the belt Q's regards width, pitch etc but there are things you need to be made aware about with this size machine.?
One of the things I found when I built my machine was that long belts where not available in 5 x 15mm HTD so depending on the X axis screw centres you may have the same trouble.?
The X screw centre's on my machine are 1300mm using 30T pulleys so needed belt length over 2750mm the longest HTD 5mm pitch 15mm wide I could find was around 2400-2500mm.
The way I got around it was to have them special made costing around £20 each. I bought 2 keeping one for spare, that was over 3yrs ago and I've only recently swapped for the spare and that was because I left a pulley lose after changing ratios from 1:2 to 1:1 for high resolution job and it fell off killing the belt in the process.!!

Regards mounting pulleys you will need the ballscrew ends machining longer than standard so the shaft goes all the way thru the pulley giving better purchase for the grub screws. Also grind a small flat on the shaft for the grub screw to grip and stop the pulley spinning.
Regards idlers and tension then You don't need lots of tension on the belt and infact if you put them under too much tension they wear quicker and it also puts tension on the ballscrew bearings and if Ott can cause binding and possible missed steps.? Just enough tension to stop the belts flapping around and jumping teeth is all thats needed and lightly tensioned idlers is all thats required. (I just use 2 bearings with large penny repair washers for guides)

I'm posting the pics of my well used setup and While my setup looks ugly and is roughly thrown together it's simple, works very very good and accurate with high reliabilty even thou I run it in some of the worst conditions for running belts.!!
I dont have any guards or shields, the machine mostly 98% of time cuts Aluminium with chips flying every where and it has never failed or lost position either thru skipped teeth or missed steps. While It's capable of max rapids around 11mtr/min with 5mm pitch screw 1:2 ratio(effective 10mm pitch) 6Nm Nema 34 motor running 75Vdc I detune it to 7mtr/min which is more than enough for my needs and also why It's NEVER, NOT WOUNCE missed steps or lost position or sync under cutting conditions or rapid movement.

To give you an idea of the resolution and what 1:2(10mm pitch) belts can achive then I've attached the Aztec calender pic with a link to video see the detail better.

Hope this helps and inspires.!

http://www.youtube.com/watch?v=wjDvi...ature=youtu.be

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