CNC Router / Mill / Plasma

[tommullin]

So, the worlds slowest project picked up some pace after starting, well, a couple of years ago. Apparently putting things in the middle of the living room helps you to not forget about them so in the past couple of weeks ive achieved quite a bit.

This one was supposed to be a bit of a compromise - I wanted it to be able to do routing, milling and plasma. Its kind of a prototype to learn some lessons before I build a better one, but who knows if that will ever happen.

Anyway, limit switches are now on, most of the bolts are in so Ive been having a bit of a play. Its quite good fun. Ive got some photos from earlier in the build, but I'm not the best at remembering - I can dig some out if anyone is interested, but its probably fairly self explanatory. I used building the frame as an excuse to learn tig. If you're suffering a shortage of m5 and m6 bolts in your area, sorry, I have used them all.

Heres a couple of photos of it (albeit a bit rusty from its time in the conservatory).

 

[tommullin]

I have no idea how ive messed those photos up so badly or what i'm doing wrong....

 

[Robotstar5]

I have no idea how ive messed those photos up so badly or what i'm doing wrong....

You are better off uploading to the forum, windows guide here or Apple version here

 

[tommullin]

@Robotstar5 - that's what I did and then used the 'media gallery embed', is that the wrong method?

 

[Robotstar5]

@Robotstar5 - that's what I did and then used the 'media gallery embed', is that the wrong method?

I've never tried the method @skotl posted, I've always used the "upload a file" box below the reply box so not sure where you are going wrong. Hopefully some one else may know?.

 

[tommullin]

nice one @Robotstar5 , I thought I needed to upload to an album first.

 

[ukracer]

Yes I would love to see photos from early in the build.

I think a few members are planning on some sort of cnc table this year...

 

[henry Kadzielski]

Good morning gents.
I built my table some 18months ago and found some build photos, so if anyone is interested I can post

 

[ukracer]

Good morning gents.
I built my table some 18months ago and found some build photos, so if anyone is interested I can post

I would be interested for certain..

 

[henry Kadzielski]

I would be interested for certain..

Lets see how I go, hope I get it right this time.

The Z drive on the gantry. Gantry is 80mm by 80mm alli extrusion. The Z axis runs on a single wide linear rail and all is mounted off it.

The routing spindle and mount. This mount just changes over from the plasma torch mount, takes about 5 min to do.

Floating head Z axis with magnetic breakaway.

Modified penumatic scriber mount. This attaches to the floating torch mount and the machine can mark then out out the part.

Yes I did screw up the picture placement, I have some pics of the stand after galvanising and two utube vids of the machine in operation cutting alli for a fuel tank. Will see if I can locate, and post better next time

 

[henry Kadzielski]

Vids as promise

And pics of machine as now

Pic of stand after galvanising

 

[tommullin]

@henry Kadzielski - I like that, looks well built. what speed are you getting out of that with the rack and pinion drive? Looks like they are servos? I'm running nema 23's all on 5mm pitch ballscrews (looks the same as your z axis setup), so i'm limited to about 45mm/s, but very little backlash.

I cant see what plasma youre using in the pics, hypertherm or have you managed to get something else to work with cnc?

I found some more photos of mine, ill post them up here now.

 

[tommullin]

I found some pics of my first attempt at building a cnc out of what was knocking around in the garage. I wanted to try and make something as a proof of concept before I bought anything. I eventually decided this was a waste of time and spent some money.


Some old drawers used to make x and y:

Trying to turn down studding without a lathe. Using a file....

I decided a power tool would be more fun.

Added a depth stop

Trying to make bearing mounts on the cheap.

Ultimately this was a waste of time. learned some stuff doing it though.

 

[tommullin]

I ended up buying some cheap Chinese generic ball screws, linear rails, stepper motors and drivers. setup a PC and tested everything using Mach3.

 

[tommullin]

I used 50x50x3mm box. Chopped up with a 4.5inch angle grinder and a 0.8mm disc.

Decided to learn tig and use this as a practice. Test welds went ok.

Learned about welding a sealed void and what happens when you do. I learned this more than once. I also learned its not as easy when youre out of position and surrounded by braces and clamps.

I didn't have a flat surface. getting this anything like square and level was a massive pain.

More welding. Mig would have been quicker.

Starting to come together. You can track the progress by the rust. I guess conservatories aren't ideal for bare metal cnc machines. who knew.

Z axis on. I think this will need revisiting. I didn't really have a plan, I just had the dimensions of the motors, rails and ballscrews. So I made this up with what I had. I just wanted maximum adjustability and thought I would redesign this at some point in the future when there were fewer unknowns.

 

[Mr Fro]

Superb!

CNC is on my list for this year so anything you stick up will be a pointer for me.

Don't suppose you've got links and/or part number for the runners and such do you?

 

[tommullin]

@Mr Fro - I bought them about 2 -3 years ago, but at the time there were loads of kits and stuff, all looked the same. same price (ish) just different kits of different sizes or you could buy what you want separately. They aren't the best quality, but they didn't rust during their time seasoning in the conservatory, which is lucky! What kind of machine are you looking to build? You going to use 80/20 aly or steel (or both like Henry)? I don't know how many more useful pictures Ive got, but if you've got any questions or anything you want any help with let me know.

I forgot to mention, I switched to Linux CNC and use fusion 360 for cad/cam. Its quite a good workflow and all free. anyone else got any decent recommendations for decent free software? I also use inkspace a bit for vector stuff.

 

[Mr Fro]

Thanks for the reply!

I've got some of that aluminium extrusion stuff ready for the prototype - I imagine I'd make something more rigid/permanent if it comes off alright.

I've previously looked at the generic kits and saw mixed reviews - I come a bit unstuck when it comes to the computery bits as that's all above my head! I've got an old laptop set aside so probably best bet is to get on and order some bits up.

Just got to clear the decks of the current jobs before I can get rolling with it...

 

[tommullin]

@Mr Fro - the computer stuff isn't too bad, but I work with pcs a bit so maybe find it less daunting. You've got a limited number of choices anyway: Windows and Mach3, Linux and LinuxCNC, or an Arduino based machine. (theres probably more but these are the most popular).

Linux and Linuxcnc are free - it works well, but its a bit fiddley.
Mach 3 is about £120odd? a windows xp licence £70? (it must be xp for mach3, not sure about mach4). - less fiddley, more help but doesn't offer much more and its money.
Arduino £10, but I'm not sure what else you need or the limitations. people seem to get them working.

I use the old printer parallel port to run my board, so it really wants to be an old desktop. I don't think laptops are very good at all. Cnc relies on timing. The pc must not have a high latency, or spend a lot of time doing operating system stuff, it needs to focus on generating pulses for the stepper controllers. If it misses its time to provide a signal, the machine could move extra steps in any given direction(s) and as its open loop (usually with steppers), you wont know so your machine will be (cutting) in the wrong place. Laptops tend to not have parallel ports and spend time doing energy saving stuff so don't perform well. You could still use one, but your machine would have to run slower and wouldn't be ideal.

I think you an get USB controlled boards now, but I haven't looked into that much. It would make PC selection easier, but this seems to work so i'll stick with until I need to replace something.

I use old pc's from gumtree for about £20, often an older simpler machine can outperform a newer one (but that's not always the case).

 

[henry Kadzielski]

@henry Kadzielski - I like that, looks well built. what speed are you getting out of that with the rack and pinion drive? Looks like they are servos? I'm running nema 23's all on 5mm pitch ballscrews (looks the same as your z axis setup), so i'm limited to about 45mm/s, but very little backlash.

I cant see what plasma youre using in the pics, hypertherm or have you managed to get something else to work with cnc?

I found some more photos of mine, ill post them up here now.

Firstly, yes they are servos, the biggest they had 850in/oz from memory.
The machine will route very comfortably at 4.5m/min. I ran out of the first routing job started out at 1.5m/min then through the software could increase the speed to 300%. Result 4.5m/min.
I normally cut thicker metal material and have a PM125 hypertherm, so don't know what speed it is capable of doing but it is in the range of over 10m/min. I have tested it on speed runs and it got scary travelling from the home position to the 1500mm position. You had to be very precise on the job button letting it go otherwise it would slam into the end stops. Yes it did and it bent my stops and made a hell of a noise. I have never tried it again. Once the machine is extended I may try it again.
The ball screw is 10mm pitch. When I built the Z drive (and the entire machine ) I had no idea what I was doing, so ended up with too much reduction on the Z drive. To combat that problem I changed the ball screw from 5mm pitch to 10mm and changed the planetary reduction from 10:1 to 3:1. I now have good Z speed. The X and Y drives also have planetary reductions 15:1. This machine was built with routing in mind, at some unforeseen time in the future. As it turned out the first job I got was to route out a school emblem out of 20mm MDF. So,so far so good, it is mach3, Corel draw, sheetcam and CandCNC hardware. The build itself was the easy part, the most difficult was to get my head around the softwares and how they go together. Any new hardware from CandCNC is now linux and you can get a computer already loaded with the software. This is where I had the most difficulty. You just don't know what you don't know.