CNC engraver / cutting machine.
- Thread starter LGB-Sid
- Start date
Found the answer to one bit (PVC) can in fact be cut with laser, the thermal process produces hydrochloric acid and toxic fumes. so I don't want a laser attachment
You don't want to high-speed cut the likes of MDF either.. The glue is a known carcinogen.
Any of these 'machines' should really be in a cabinet, with suitable dust/fume extraction and control..
I think MDF gives off formaldehyde when machined, I believe some states in the USA are quite fussy about its machining.
B&Q won't touch MDF on their free cutting service. I had to use a hand saw on two 8' x 4' sheets out in the car park a few years back.
I used a hand router on on lots of exterior grade MDF sheets a few years back, as I made a full size Willys jeep out of the stuff I can remember feeling quite crap each time I cut the stuff 
, it took weeks of cutting to make the thing , It was all built on MK I escort running gear
I only intend cutting PVC foam board on this machine.
I can remember feeling quite crap each time I cut the stuff , it took weeks of cutting to make the thing , It was all built on MK I escort running gearI only intend cutting PVC foam board on this machine.
I can answer the question myself soon , I bought one, it's all assembled now, and the software sorted from what I know and use Autocad, to the software that drives the machine. So the next test is add some material to it, put a cutter in it and press GO 
and generate what looks like snow....... lots of it I bet 
and generate what looks like snow....... lots of it I bet
In a previous existence...
'We' built a computer controlled router-doo-hickey.. This in my Broken Biscuit Company days..
Obviously, all controlled from a BBC Model B.
Our biggest problems were keeping dust out of the computer, and drive electronics. Then keeping the stepper-motors cool. - Big holding-currents to keep things still, and avoid any backlash.
From experience:
If you try to use a domestic vacuum, as a dust extraction machine.. It does not like the fine dust created, or running for several hours at a time.
Oh, and domestic vacs. are pretty noisy, after the novelty wears-off!
'We' built a computer controlled router-doo-hickey.. This in my Broken Biscuit Company days..
Obviously, all controlled from a BBC Model B.
Our biggest problems were keeping dust out of the computer, and drive electronics. Then keeping the stepper-motors cool. - Big holding-currents to keep things still, and avoid any backlash.
From experience:
If you try to use a domestic vacuum, as a dust extraction machine.. It does not like the fine dust created, or running for several hours at a time.
Oh, and domestic vacs. are pretty noisy, after the novelty wears-off!
According to what my Mum told me when I was a teenager, that could save your eyesight.
David
I've done a little work with CNC router/engravers. To my eye the spindle in that one looks a bit small and feeble. It will be loud and dusty. If you want to cut as well as engrave, workholding can be a bit tricky. Depending on the material you pick and the exact cutting tool you use with it, tear-out of the surface can be a problem - not sure about the card part of foamboard. Dust removal is a must because otherwise the tool ends up drowning in already-cut dust and building up heat. So, it can be good, but the space and setup requirements are quite a bit more than it might look at first sight.
First tests done and I didn't spontaneous combust in a cloud of fine dust I bought the machine just to cut plastic and PVC board, no tree trunks as in the first pic, so it should have enough power to do that job. Clamping is easy with PVC foam board ,double sided tape , works perfect and is a pain to get the piece off the sacrificial bed I added so it ain't going to fly off in a hurry.
First test was a 1mm end mill set to cut 1mm wide slots it made a right mess of the job. The next three tests were done using a 20 deg engraving bit set at different speeds and getting 0.5mm deeper on each test. Results were better but still needs work to find the best bit and speed and depth to cut the PVC. I still have three weeks to test before I need to return it if it won't do the job , but looks promising so far for what I have in mind for it to do.
I bought the machine just to cut plastic and PVC board, no tree trunks as in the first pic, so it should have enough power to do that job. Clamping is easy with PVC foam board ,double sided tape , works perfect and is a pain to get the piece off the sacrificial bed I added so it ain't going to fly off in a hurry.First test was a 1mm end mill set to cut 1mm wide slots it made a right mess of the job. The next three tests were done using a 20 deg engraving bit set at different speeds and getting 0.5mm deeper on each test. Results were better but still needs work to find the best bit and speed and depth to cut the PVC. I still have three weeks to test before I need to return it if it won't do the job , but looks promising so far for what I have in mind for it to do.
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To my eye the 20/s one with a light sand looks pretty good, most certainly so from a normal viewing distance.
Same here, that's cut at 1mm deep which is probably around what you get when you score this stuff with the screwdriver technique, think I will try going the other way next and speed up the traversing speed which is what the 20/s is 20mm horizontal travel / sec, just to see if the cut improves or gets worse
First tests done and I didn't spontaneous combust in a cloud of fine dust
First test was a 1mm end mill set to cut 1mm wide slots it made a right mess of the job. The next three tests were done using a 20 deg engraving bit set at different speeds and getting 0.5mm deeper on each test. Results were better but still needs work to find the best bit and speed and depth to cut the PVC. I still have three weeks to test before I need to return it if it won't do the job , but looks promising so far for what I have in mind for it to do.
View attachment 257706
Might be telling you how to suck eggs but for perfect cuts on the face (IE a clean edge) you wont a down cutting bit with a high feed rate and low speed on the spindle to avoid melting, less passes the better but that might not be possible with a smaller machine.
Hi I have control of the feed rate speed, the spindle speed, max is 9000 rpm, and the number of passes cutting depth per pass sets that, the best looking one so far on my tests was the 20mm / sec feed rate which was cut with two passes 0.5mm per pass. The next test was going to be a single pass, 1mm cut depth and then play with the feed rate speed and the spindle speed to see if I can improve the edge of the cut. I am sure with a bit more testing I should be able to get it to cut patterns for me cleanly.