Planning a mechmate build in Cape Town South Africa.

[starkec]

Hi all,

Ive been lurking in the forums for about 6 months now and I have subsequently decided that the Mech Mate is definitely the machine for me.
I have previously built a 2x3m foam cutting machine for building model aircraft parts. But now i think I'm ready to upgrade to a full blow MechMate machine. This is hopefully going to be a project for my 5 week university vacation during July. Due to the somewhat limited build time I'm trying to make a parts list and order all the parts before that time. I do have a somewhat limited budget as it must be approved by my father before i can start. My father and I have built 2 light aircraft and Im currently restoring a 1983 Minin clubman, my father is an Electrical engineer and specializes in computer programing, so hopefully between the two of us we will have all the skills required. Any advice on my part selection will be greatly appreciated.

So time for the first of possibly many questions. This is my thoughts for the basic motor/ controller and power supply setup

Stepper motors - 86HS9801

Stepper Drivers - DM856 stepper driver

Bob - MACH 3 BREAKOUT BOARD

Now if my calculations are correct i need a supply voltage of 65V and approximately 11 amps which means i need a 715VA power supply. Do any of you South African MechMate builders know where i could get a supply locally like that? Also if I run the steppers in parrelel i get the figure of 47 volts for a supply, I can get a 400VA 48v supply locally so would that be a better option?

Any comments will be greatly appreciated

Chris

[Alan_c]

Welcome Chris

Good choice of break out board (Greg is great to deal with and offers good service and products) I am not familiar with the stepper motors or the driver - I use the Gecko 203V and am very happy. Your power supply requirements seem a little big, but that may be because of the motor and drive specs, anybody else using Deitech that can advise?

[danilom]

48V in series , but then you will loose some rpm's

DM856 are really nice, two days ago we used a smoothstepper with them and they really sound like servos working without any noise.

[starkec]

@ Alan thanks for the re-assurance on the Bob, I see you are in Grabouw may I ask who did your laser cutting and bending for you and where you sourced your steel, if you dont mind me asking. I see in another post you talked about Schuurman Laser Cut in Sacks Circle and Vulcan Steel in Montague Gardens. I was just wondering which one you used and how well it worked out. Thanks

@ Danilom What power supply do you use for your setup? And if I go the 48V route what sort of VA do you think i will need? I would have liked to have gone the smoothstepper route due to its usb rather than parallel port operation but it seems that all the locals highly recommend the bob i listed above due to easy setup and customer care. Are you using the same steppers or just the same controllers?

Thanks for the help so far guys

Chris

[Alan_c]

Chris
I have used both and their cut and work quality is good, I found Vulcan to be quite a bit cheaper, but get quotes from both. Macsteel would be a good source of steel, but shop around and try the smaller vendors for cut to length sizes on those sections that dont require full length stock. I live in Grabouw but my machine is based in Ottery.

[danilom]

we used on 3 machines 9802 motors, but for DM856 drives becouse they are only 5.6A max and 80V its better to use 9801 (4Amp) and high voltage which drive supports.

on Pajka's machine for five 9802 (5A) steppers we used 17Amps 34V power supply
on mine I had a 15Amp EI transformer so I used that.

Just get the toroid transformer or EI core, connect it ti 35A bridge rectifier and 20.000uF capacitors.

[starkec]

Thanks again guys,

Ive asked for a quote for the cnc cutting and Im still busy investigating power supplies so hopefully those will come through soon. And now for yet another question, for direct drive motors what rack and pinion should i use? No matter how much i search i cant seem to find an answer.

Chris

[hennie]

Hi Chris,You can ask Greg for the power supply he will be able to help.