Machsupport Forum
General CNC Chat => Building or Buying a Wood routing table.. Beginnners guide.. => Topic started by: bfgstew on August 04, 2015, 05:16:25 PM
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Hi all,
I have built a router/milling machine basically out of scrap parts, with a few bits made via a friend. Now I have had it running dry as I have no cutting head at the moment and am waiting to buy a Kress 1050 head, once in my hands I can get cutting. It is going to be used mainly to cut plywood and MDF with the odd bit of Aluminium work, nothing big though. Now in the video you can see it moves fairly slowly compared to many others, this is down to using M16 X 2 pitch screwed rod for the leadscrew, the stepper for the Y axis is a VEXTA PH299-4.6 and the steppers for X and Z are VEXTA PH268-1.6, again these use M16 x 2 pitch screwed rod for the leadscrew, the drivers for the motors are what was used when they belonged to the labelling machine originally so data for them is non existant but they work, this is conected via a cheapo BOB to my PC running XP.
Now during testing and setting up I can get it running faster than the video shows but it stalls if I push it past 1300 in MACH3 motor tuning, on investigation the data for the motors show the torque at less than 1Nm (0.883 to be precise) not sure about the 299 motor though as I can find no data for it, but am presuming this too will be on the low side on the torque front. So this got me looking into improvements and a load more questions than answers. The upshot is would it be better to use 16mm x 5 pitch ballscrews for all axis's? Change all the motors to a NEMA23 Hi torque motors (4Nm)? And have 2 motors run the Y axis instead of 1 running 2 belts as I have at the moment. This will obviously require new drivers and a new power supply, with the amount of different manafacturers and suppliers I am getting baffled by the complexcity of choices, can someone please point me in the right direction, cost is the limiting factor as I can't afford the likes of GEKKO drives but don't want to buy stuff that's not going to last 10 minutes......................ideal world, cheap but reliable and UK if possible.
Video of my machine...................https://www.youtube.com/watch?v=nG2lSQl4IQ0 (https://www.youtube.com/watch?v=nG2lSQl4IQ0)
Many thanks in advance
Stewart
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Another thing I forgot to mention is the fact that the driver is only capable of either full or half step, and I am not going to attempt to try and get it to half step as it means soldering a +5vdc supply onto the drive boards themselves as I said these boards were built originally for a labeling machine and not for a CNC!!!!!!, but they were free. So with just full step available when it is running and say going in a circle the noise from the Y axis stepper as it slows down at the base of the circle is awful to say the least so my thinking is if I can micro step that should remove the noise from the steppers?
Sorry if I ask to many dumb questions.
Stewart
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Another thing I forgot to mention is the fact that the driver is only capable of either full or half step, and I am not going to attempt to try and get it to half step as it means soldering a +5vdc supply onto the drive boards themselves as I said these boards were built originally for a labeling machine and not for a CNC!!!!!!, but they were free. So with just full step available when it is running and say going in a circle the noise from the Y axis stepper as it slows down at the base of the circle is awful to say the least so my thinking is if I can micro step that should remove the noise from the steppers?
Sorry if I ask to many dumb questions.
Stewart
Hi Stewart,
Unfortunately you are stuck with the full or half step that your drivers provide (micro-stepping is only provided by the actual stepper driver chips so you will need to change them to get it ). Gecko G540 comes to mind ;)
Tweakie.
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Having the Machine SING to you is the CHARM of a stepper machine (;-) . I can tell what it is doing simply by the Song it is singing.
AND you can actually play real music with it.
If you cannot afford Ball screws then consider acme screws with antibacklash nuts in a proper pitch for CNC.
Just a thought, (;-) TP
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Hi Tweakie,
I am just thinking long term, if my CNC works and am happy with it, I am looking to increase its footprint and upgrade the electronics and mechanics of it, as I say it has been made purely from scrap and junk, so far it has cost me nowt other than my time.
Hi BR549
Now there is singing, and there is singing, mine shouts and it ain't very pleasant, hence the need for micro stepping and ballscrews.
I am looking at stuff on CNC4YOU, looks reasonable quality and prices are in my ballpark, has anyone dealt with these guys?
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For a router, you want 10mm pitch ballscrews. Eventually (in about a day or two), you'll find that even 5mm will be too slow.
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Hi Gerry,
I aim mainly to be cutting between 2mm and 6mm ply, using a 1mm or 2mm endmill, with the odd excursion to MDF and Aluminium, would a 10mm pitch ballscrew still be the route to go?
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If you'll only be using those small tools, then 5mm should be OK.
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Was looking at these bits of hardware, are they to good to be true price wise?
http://www.cnc4you.co.uk/Ballscrew/Ballscrew-with-Fitted-Anti-Backlash-Ballnut-RM1605-C7-16mm (http://www.cnc4you.co.uk/Ballscrew/Ballscrew-with-Fitted-Anti-Backlash-Ballnut-RM1605-C7-16mm)
http://www.cnc4you.co.uk/Nema23-Stepper-Motor-4Nm-60BYGH401-03 (http://www.cnc4you.co.uk/Nema23-Stepper-Motor-4Nm-60BYGH401-03)
http://www.cnc4you.co.uk/Microstepping-Driver/Digital-DSP-Stepper-Driver-5.6Amp-50Volt-CWD556 (http://www.cnc4you.co.uk/Microstepping-Driver/Digital-DSP-Stepper-Driver-5.6Amp-50Volt-CWD556)
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Eventually found details of the driver boards I am using, so gives me a better chance of setting up and understanding the workings of them.
For your info if so inclined................http://www.google.co.uk/url?url=http://www.ahs-antriebstechnik.de/pdf-dateien-e/STep%2520Motor%2520Drives/ZMP%2520Manual%2520English.pdf&rct=j&frm=1&q=&esrc=s&sa=U&ved=0CBQQFjAAahUKEwjQx6iIuZzHAhWlcdsKHamiCVM&usg=AFQjCNGl7dm-s_4a-unKIKxX0-5wITYOnA (http://www.google.co.uk/url?url=http://www.ahs-antriebstechnik.de/pdf-dateien-e/STep%2520Motor%2520Drives/ZMP%2520Manual%2520English.pdf&rct=j&frm=1&q=&esrc=s&sa=U&ved=0CBQQFjAAahUKEwjQx6iIuZzHAhWlcdsKHamiCVM&usg=AFQjCNGl7dm-s_4a-unKIKxX0-5wITYOnA)
The ones I am using are the ZMP 92-70 boards
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CNC4You sells pretty decent stuff at good prices.
The ballscrews, being C7, aren't the best of quality, however they're more than good enough for most machines. They'll certainly be a major improvement over any non-ball type screw. C7 will make them a rolled screw with not the best of tolerances, but perfectly good enough unless you're striving for the ultimate in precision.
The stepper motors are well recommended, so no issues there, and the drivers are pretty generic but good quality.
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Thanks for that @mc, appreciate honest recommendations, so will be getting stuff off them in the near future.