Router Build number 2

[charlieuk]

just trying to get the basics down see what you think.

the frame is the 100 x 100 x 5 steel tube i was given

I have the two top rails mounted on plates on top of the short verticals to allow for shimming. I will see get the top rails machined flat before so and maybe one with a straight edge down it for the linear rail to butt up to.

I need to obviously put some diagonals in somewhere I guess

at the moment I have the 3 cross members at 50 x 50 x 4mm with 330mm centers ?

[charlieuk]

I did a little more adding the rail detail and some diagonals.


I keep reading about everyone using the aluminium L style gantry, is this only suitable for wood cutting? would I be better off with a steel arrangement for cutting aluminium?

[charlieuk]

I have put a gantry together using 45 x 90 kjn extrusion as I think dean said you can bolt bk blocks and bearing straight to it I have it sitting on 20mm plates on the carriages and 20mm end plates.

I have only put the drawing together to get a bit of a idea if I'm going in the right direction, dimensions may need to be altered.

Any one got any comments on this? does it need to be beefed up or made in steel to get high quality cuts on alli?

[charlieuk]

Does any one have any comments on what I have done so far?

Can any one offer any advice on what ball screws to go for for the x y and z axis?
was thinking of running two screws on the X linked by belts

many thanks

[1Jumper10]

It looks like a solid design to me. I dont think you'll have any problems with your frame not being rigid enough. I think twin ballscrews, one each side is a better design than one down the middle. They're easy enough to synchronize either with belts or just dual motors. But, I've never built a machine with ballscrews so judge my comments accordingly. Its very possible I may be totally wrong :)

[Boyan Silyavski]

Does any one have any comments on what I have done so far?

Can any one offer any advice on what ball screws to go for for the x y and z axis?
was thinking of running two screws on the X linked by belts

many thanks

When you are in front of the machine X is left right, Y and A are the long axis. Its called "the right hand rule"




So on your question, i will always prefer 2 motors each belt driving via reduction or not the separate ball screws, versus 1 motor belt driving both ball screws at once. While second is a fool proof way to do it, its more difficult to set up, dust protection will be needed for the belt, motor and drive have to be more carefully matched to the machine. Plus tension to the belt must be right to function properly and there is more possibility for misalignment. In other words i choose the simpler way to do things. So at the end of the day= there is no better way. its all the same if done right. The result i mean.

PS. Also comes to my mind that the one motor design could not be 100% suitable for very fast and heavy machines say 20-30 meters per minute and serious acceleration. Not that there are such in the majority of the DIY builds. Its one thing to put much pressure on 300 mm belt and another on 3 meter belt

[charlieuk]

how is the CSMIO/IP-M now with dual motors? I know there was talk about it a few years ago

[Neale]

how is the CSMIO/IP-M now with dual motors? I know there was talk about it a few years ago

I was one of the people asking about it, because I was trying to decide whether to go one big motor/long belt or two motors, one per ballscrew. In the end, I went the two-motor route with an IP/M. There are probably two issues - initial homing and keeping sync when running. Second point first - I have had no problems with the two motors staying in sync when all is running well. I set up the IP/M as per the manual and it does what it says on the tin. I use EM806 digital drivers with stall detect and they trip if one motors stalls (which has generally been when I've been pushing the machine a bit). Fault signal goes to safety relay which signals IP/M and everything stops with no damage.

Now - homing. I spent some time initially squaring the gantry, using the "four pins in a square and measure diagonals" method. I have inductive proximity switches as home switches on both ends of gantry; one is wired to the IP/M and the other is not. Well, it is really but not configured in Mach3. When machine is first switched on, I home all axes as usual (configured so X and Y home simultaneously to save time). I then hit estop which cuts power to motors. I tweak the slave axis pulley by hand, simulating the Mach3 homing process and watching the led indicator on the switch. That is, I wind the screw until the light goes out, then slowly wind it the other way until it relights. Reset estop, re-home just to make sure (only takes a second or two) and I'm set to go for the rest of that session. Unless estop is triggered for some reason I never go through the manual process again for the rest of that session; on the odd occasion when I've checked it's been bang on. Generally it's close enough even after shutting down and restarting later. Because of the motor cogging effect, I'm probably no better than the nearest full step doing this. So, that's to within 0.025mm at the end of a 1000mm gantry. Probably good enough for a machine used primarily for wood.

I've thought about adding a little bit of complexity which would do a proper master/slave homing job. With a lesser motion controller with the usual 5V single-ended signalling this would be easy but the IP/M lets me use differential connections to the drivers and 24V signalling which complicates putting an extra bit of electronics between the two. On balance, I would rather keep differential signalling and the manual homing. And yes, I know it's not that difficult to put the electronics together, but it's more effort than just sticking an Arduino board in there. Or I could have spent nearly three times as much for an IP/S...