New Machine Build- 3'X4.5' router project

[stangtjk]

I'm planning on building a cnc router mainly for cutting wood and foam. I've already began gathering up some parts and started designing the machine in solidworks.

I have 4 IM483H drives and 3 IM805H drives. The 4 IM483H drives were used and are already mounted to a pcb with a rectifier for DC power. The 3 IM805H drives appear to be new and are each mounted to their own pcb.

I've also got 4 parker os22b stepper motors off ebay. They may be a little small but couldn't pass them up for $50 for all of them.

The rails I'm going to be using are rollon 43 series. I figure they would be more forgiving than profile rails because they don't need as precise of a mounting surface and they were cheap.

I'm considering doing a belt drive for the x and y-axis and buying a screw driven linear actuator from ebay for the z-axis.

Here are the parts I've accumulated so far.


This is the basic design I'm working on.


I'm not sure if I should drive each side of the gantry independently or run it off the same shaft.

The design as shown is 40"x66" and should have a cutting area of around 35"x54". I plan for the gantry to be made out of aluminum and the base will either be aluminum or steel.

As I am new to CNC any advice would be welcome. I don't plan to do anything requiring high tolerances however I still would like to have a pretty solid machine. I'm trying to stay below $1k for the whole table.

[jalessi]

Stangtjk,

A OS22B / IM483H combination may be a futile experiment.

IM805H at 75 volts will be better since the OS22B "B" winding is 170 volts.

Jeff...

[stangtjk]

I know that's what the sticker says but in the specs it lists the parallel inductance to be 4.2mH. The equation 32*sqrt(mH)= power supply voltage would suggest a 65.5V power supply which had me a bit confused. I thought maybe the 170V was if they were wired in series. I don't know much about it but I thought based on the inductance they may work ok with ~45V. If they don't work out I'm not out much, I'm sure I could relist them on ebay and get most if not all my money back.

[jalessi]

The motors will function with 45 volts, the question is will they move your gantry at a reasonable speed.

Please keep us posted on your progress.

Jeff...

[stangtjk]

I picked this up today from ebay for $20, I'm planning on using it for my z axis.

I cant find a data sheet for these models (12G2) on the IAI website but I think I saw one partially disassembled on another listing and it used 2 profile rails and a ballscrew. It comes with the Super SEL type A controller but I wouldn't have a clue on how to use it so I'm gonna try to swap the servo for a stepper motor. If not I'll just salvage the linear motion parts and make my own assembly.

[stangtjk]

I've been scouring ebay and the net looking for the best deals for belts and pulleys and have adapted my design to fit what I could find cheaply.

I've decided to use 12 tooth 3/8" pitch (L) pulleys for the x and y-axis with 3/4" belts. There is a seller on ebay that is selling lots of 25 pulleys for only $37 shipped. I don't need 25 pulleys so I asked him if he could sell smaller lots and he set me up a lot of 6 pulleys for $15. That's about the price of one pulley at spd-si. I'll need about 27ft of open ended belt which I found at polytech design for $2.46/ft.

For the gear reduction I'm going to use 1/5"pitch (XL) pulleys. I found some used 48 tooth aluminum pulleys on ebay. Picked up 3 for $23. I think I'm going to run a 10 tooth pulley on the motors. I found them at MSC Industrial Supply Co. for $2.15 each. The same place has the 11" belts I need for $5.62 each.

If I added everything up correctly the price for all my belts and pulleys is around $140 give or take a few dollars.

[stangtjk]

I received the linear actuator today. It needed cleaned up a bit but its seems to be in excellent shape mechanically. I partially disassembled it to inspect everything and clean it up a bit. The ball screw appears to have 8 1/4" of travel and an 8mm lead, I did not notice any backlash at all. The rails are nsk LS15. Here is a picture of it after I cleaned it up.


It looks like there is plenty of room to swap out the servo for a stepper motor, just need to fabricate an adapter for the mount. The unit is heavier than what I was expecting. It weights about 15lbs.

[stangtjk]

I think I've got my design figured out now. I bought a piece of 4590 extrusion from 8020 on ebay that I plan to use for the gantry beam.

At first I though I could get away with one rail on the gantry because they seemed pretty solid but I was looking at the specs and the bearings are only rated for a moment of 23.6 Nm about the axis of the rail. I decided to change the orientation and use one on the top and bottom of the gantry beam. Now I need to either get another rail or shorten my design. I think I'm going to go with the latter to try to stay under budget. Cutting dimension are now around 33"x34"x8".

Anyway here is what its going to look like (still missing a few small parts, brackets and such but its mostly there).




And a rather poor render just for fun

[stangtjk]

I'm considering selling the 4 axis driver board I have and buying a servo drive for the Z-axis rather than swapping the servo for a stepper. I'll use the IM805H drives I have for the X and Y axis. If anyone would be interested PM me. It looks like a nice board however I have not yet had a chance to test it. It has 4 IM483H drives mounted to it and they are rated for 48V 4Amps peak. I think these drives new cost around $250 each. The board has a rectifier circuit on it also so you just need to hook it up to a suitable transformer which I'll include as well (should supply 41V @ 10A after the rectifier). A 5V power supply is also already integrated into the board.

Here are some pics if anyone is interested.