Hello,

I have recently started designing my first CNC machine
The dimensions the cutter can reach are about 90cm x 70cm x 10cm

As for the linear bearing I use the following parts:
20mm steel rod for the x and y shafts. for the x axis I will support this rod in the middle to prevent bending.
the bearing itself consists out of 2 bended (120 degree) plates (4mm thick) welded on a plate for fixture. on these plates i connect some bearings (6 on every side)

for the Y axis i'm not sure weather I'll use a sliding bearing or the same bearing as described above.

The z-bearing is a sliding bearing on a 15mm shaft.

I already bought 3 1.7Nmsteppers and for the drivercard i'm building the PICstep at the moment. I have some trouble finding a shop that sells the IC DIGIKEY LMD18245T-ND over here in Holland. I can order them at digikey, but i don't know if i have to pay taxes and importing costs etc. Does anybody know where to find them in europe?

every comment on the design is welcome since i'm not sure weather the design is stiff enough.

Many thanks

Hendrik

I believe you can buy them at farnell (www.farnellinone.nl) as a private person (not a company) if you pay in advance.

Another (cheap) way is to sample them.
Look for it at the National Semiconductor site.

Your design looks nice.
If you have concerns about stifness do a search on the forum on "torsion box
"

succes

Another (cheap) way is to sample them.
Look for it at the National Semiconductor site.



This is how I got my LMD18245, i was able to get 5 at a time, i had to pay postage but that is still cheaper than buying them outright.

I have to say the picstep board is a great design and works well for me.

Good luck

You might add a flat plate across the back of your Y axis for stiffening that up. I see you have a single support in the center for the Z axis bars. If you can find some extruded T material, or even angle to support it's entire length.... I opted to go with a stationairy support for the Y and Z axis and move a small (light wieght) table under it in the X axis. I've only been to one electronics store in the Netherlands, and that was in Rotterdam many many years ago. Ditto on the National Semi sampling, have done that with success on other parts.

I placed this thread on the wrong place. the other thread is placed here:

http://www.cnczone.com/forums/showthread.php?t=30076