First CNC machine

[Tom]

Hi Kev, it' looking good - loads of progress...

I cant help you with the rails & carriages (I made my own), but I like your whiteboard sketches! I do alot of thinking out loud on a whiteboard in my workshop... Can't beat it...!

[Ross77]

Thats a shame, I didnt think you would have a problem this soon.
Is it binding because of the long distance of the y compared to the truck spacing or is it just the weight causing excesive friction? If its the former then it should disapear if you drive it with a screw on each side. (eliminate the racking) might be worth pursuing before for you make major changes.

For the rails I beleive Gary at Zapp sells the 15mm rails and 4 way loading trucks for the same as the Igus stuff you bought. £50-60 for 1m rail and £35 ish a truck. These also have way more capacity as well.

[kev]

Thats a shame, I didnt think you would have a problem this soon.
Is it binding because of the long distance of the y compared to the truck spacing or is it just the weight causing excesive friction? If its the former then it should disapear if you drive it with a screw on each side. (eliminate the racking) might be worth pursuing before for you make major changes.

For the rails I beleive Gary at Zapp sells the 15mm rails and 4 way loading trucks for the same as the Igus stuff you bought. £50-60 for 1m rail and £35 ish a truck. These also have way more capacity as well.

I have been playing with it today, i had one screw in each bearing block tightened up, one side of the frame loosened off so it would move but it is still binding and hard to move, i even tried adjusting the bearings but no joy.

I took the y axis frame off leaving the 2 plates on, and if u put any slight sidways pressure on the plate it locks the bearings up.

It could be due to the y axis being so big compared to the bearing spacing.

Hopefully work should be ordering the 20mm rails and carriages from zapp, they should be alot better due to having bearings, and they only work out to be about 40 quid more than the igus set.

Im going to try the igus rails on the y axis where everything should be more square and closer together.

[Ross77]

I have been playing with it today, i had one screw in each bearing block tightened up, one side of the frame loosened off so it would move but it is still binding and hard to move, i even tried adjusting the bearings but no joy.

Sorry I meant the ballscrew/leadscrew

I took the y axis frame off leaving the 2 plates on, and if u put any slight sidways pressure on the plate it locks the bearings up.

With a leadscrew on each side and linked with a belt, (which you will need anyway with the ball bearing rails) then both sides would be moved evenly and should'nt bind.

but then again if you can get the bearing type then that will solve everything. I've got 20mm THK's and they are solid..

If you are still going to use the igus on the y axis then try to follow the design guide on the width to truck spacing ratio, also make sure the leadscrew is perfectly in the middle otherwise you will have the same problem with binding....especially with the 250mm z axis.

I would try again with the igus on the x axis with twin lead screws and use the bearing type on the y axis. just my 2 penneth

out of interest what are you using for the spindle?

[kev]

Sorry I meant the ballscrew/leadscrew

With a leadscrew on each side and linked with a belt, (which you will need anyway with the ball bearing rails) then both sides would be moved evenly and should'nt bind.

but then again if you can get the bearing type then that will solve everything. I've got 20mm THK's and they are solid..

If you are still going to use the igus on the y axis then try to follow the design guide on the width to truck spacing ratio, also make sure the leadscrew is perfectly in the middle otherwise you will have the same problem with binding....especially with the 250mm z axis.

I would try again with the igus on the x axis with twin lead screws and use the bearing type on the y axis. just my 2 penneth

out of interest what are you using for the spindle?

I have not got any leadscrews yet, im just trying to get the frame made up and running smooth, at the moment the X axis is very stiff and would give the stepper motors a good workout.

i think i am going to run a motor each side on the X axis.

I have sort of fallen out with the igus bearings haha, the difference between them being sort of moving and locking up was half a screw turn on one of the carriages.

for the spindle i was looking at using a kress, are these any good for cutting aluminum?

[irving2008]

for the spindle i was looking at using a kress, are these any good for cutting aluminum?

Up to a point... as long as you keep the depth of cut small and get a reasonable feed rate and stick with 1 or 2 flute cutters...

[kev]

Up to a point... as long as you keep the depth of cut small and get a reasonable feed rate and stick with 1 or 2 flute cutters...

Ok what would be a better choice?

[kev]

Hi Kev, it' looking good - loads of progress...

I cant help you with the rails & carriages (I made my own), but I like your whiteboard sketches! I do alot of thinking out loud on a whiteboard in my workshop... Can't beat it...!

Ha ha yea its sometimes easier to just sketch ideas down.