[imbaine13]

I think I can now move forward now that the linear bearing issues are history.

[skrubol]

Hello Miller,

I see what you mean from the videos and also agree that "closing the box" makes a huge difference, which is why I did it right from the start. I also had a closer look at your I-beams (which look beefy), and if you're saying they deflected by 4cm under a 50kg load, then I'm a little worried about mine, mostly because my set up isn't anywhere close to the level of rigidity you've got in yours!

Didn't he clarify he was talking hundreths of a mm? So that would be 40 microns, or around 2 thou(sandths of an inch.)

[imbaine13]

Didn't he clarify he was talking hundreths of a mm? So that would be 40 microns, or around 2 thou(sandths of an inch.)

I thought he meant 4 centimeters. I think we can all agree that 40 microns (4 hundredths of a millimetre) of deflection is more than perfect for a DIY machine, besides, the equipment required to take such measurements is beyond most DIY builders. I'm thinking it's either 4 millimeters (0.004 metres) or 4 centimeters (0.04 metres).

[skrubol]

Yes, I had about 4 "centiemes" of flex in the I-beams, which I reported as 2 thou.

4 centimeters ( french ) hundreds of a mm

I thought he meant 4 centimeters. I think we can all agree that 40 microns (4 hundredths of a millimetre) of deflection is more than perfect for a DIY machine, besides, the equipment required to take such measurements is beyond most DIY builders. I'm thinking it's either 4 millimeters (0.004 metres) or 4 centimeters (0.04 metres).

40 microns is about 1.6 thou, so I'd think that is what he was saying.
4mm is a LOT of flex. 40 micron is not bad for a woodworking router but wouldn't be good for metal, as machining forces would cause a lot of vibration.

[wmgeorge]

I thought he meant 4 centimeters. I think we can all agree that 40 microns (4 hundredths of a millimetre) of deflection is more than perfect for a DIY machine, besides, the equipment required to take such measurements is beyond most DIY builders. I'm thinking it's either 4 millimeters (0.004 metres) or 4 centimeters (0.04 metres).

You can purchase 25 mm solid steel round bar stock and support from the bottom like my Chinese machine I briefly owned. They make linear bearings to fit that bar with a opening at the bottom to accommodate that bottom support web. The angle grinder was going to use a flap disk to take off the scale. I have a pretty good skill set in steel fabrication success after 60 years .

https://www.automationdirect.com/adc...n_(mechanical)

https://www.ebay.com/i/253140963047?chn=ps

I realize your in Uganda but you have internet and order from China. All this can be found online and even China or eBay.

[imbaine13]

Hope everyone's okay. After a long time busy, I finally managed to score some free time and resume this project. Made an entirely new design using angle iron. The square section wouldn't work because the sides aren't exactly parallel, therefore, it was hard lining the holes on either end of the pipe. Even the angle iron I ended up using isn't exactly 90 degrees, but it's a lot better than the square tubing.

[imbaine13]

Some uploads.

[imbaine13]

For some reason, the sketch up model wouldn't upload. I'll keep trying. The problem I had before where the motion of the axis wasn't smooth was solved. I got better quality bearings and smooth pipes for them to roll on. The pipes may have thin walls (1mm I think), but for now they seem to be working without caving in. I'll keep monitoring them.

[imbaine13]

Some photos.

[imbaine13]

Some of the photos seem to have been rotated. My apologies.

[imbaine13]

More photos.

[imbaine13]

Last few photos.

[imbaine13]

I think you need to add a a brace to the motor mount at the end of the machine to stop it flexing.

If you're talking about the X - axis motor mount (which drives the gantry), the pieces if angle iron I used for attachment secured it quite strongly. I'll see how it goes as I build on.

It looks like a machine that you will easily be able to develop and refine as time goes by and ideas come to you.Do you have any stepper motors or drivers yet?Building a case for the electrical components and laying out the cables in a logical and tidy way takes quite a lot of thought.

It is indeed. Best of all, I like how adjustable everything is. I have the stepper motors. Ordered some BED's (big easy drivers) a few weeks ago but the pandemic has delayed the shipping. The plan with cable management is to lay everything out on a panel of MDF and make a neat box using the machine to accommodate the electronics and electricals later on. I'm a little concerned about dust management most since I'll be running it indoors. I think enclosing the whole machine in a sound proof box will be more effective than a vacuum whose noise will be extremely amplified by the room.

[imbaine13]

Got some work in a few days ago.
Behold the Z - axis rails. I'll be working on the Z - axis tomorrow.

Sent from my SM-J250F using Tapatalk

[imbaine13]

So far I'm pleased with how the machine is turning out. All the rails glide very smoothly! I'm kind of in a hurry to get it up and running now because there's a huge line up of work waiting for it. I also plan to build a P.C case using MDF + acrylic cut from it. There's a few bits (especially the Z - axis) that I will definitely have to rout out of MDF and replace to increase the work area.

Sent from my SM-J250F using Tapatalk

[imbaine13]

I'm a little concerned about dust management most since I'll be running it indoors. I think enclosing the whole machine in a sound proof box will be more effective than a vacuum whose noise will be extremely amplified by the room.

That's a something I hadn't taken seriously before that has started to haunt me as well! I might take the route of the enclosure coz vacs are loud and require additional power to run. To keep noise to a minimum, I might have to use a very low power spindle.

Sent from my SM-J250F using Tapatalk

[skrubol]

How come the Z axis rails are so far away from the carriage? Those little threaded rods are going to flex a LOT at that length. You will need to add a lot of triangulated bracing if you want to get decent results cutting anything harder than styrofoam.

The problem with a sealed box and no vacuum (or compressed air,) is that the chips you're cutting will just pile up on what you're cutting and cause lots of problems if they aren't cleared away frequently. When cutting wood you can easily start a fire.

[Dec0y]

As many have said your design will be plagued with lots of movement.
It appears you are fixed on your design but I urge you to reconsider your design
I would recommend you consider a fixed gantry moving bed or high fixed walls for your Y axis that a low gantry rides on.

take alook at this video

https://www.youtube.com/watch?v=ALvNohdBHb4

[aarggh]

That's a something I hadn't taken seriously before that has started to haunt me as well! I might take the route of the enclosure coz vacs are loud and require additional power to run. To keep noise to a minimum, I might have to use a very low power spindle.

Sent from my SM-J250F using Tapatalk

Aside from the serious trouble you'll have with the machine flexing in every direction in use, relying on a dust enclosure will simply clog up every single part of the machine that moves with dust, which will make things run roughly, and with more flex when the bearings are riding on clumps of built up dust. Wherever possible you need to remove dust at the source, in this case at the cutter.

Water cooled spindles are very quiet, and will be the most ideal solution for machining indoors, and as you'll have dust problems, they won't be affected by the dust like an air cooled one would be, which would be noisier anyway.

[imbaine13]

How come the Z axis rails are so far away from the carriage? Those little threaded rods are going to flex a LOT at that length. You will need to add a lot of triangulated bracing if you want to get decent results cutting anything harder than styrofoam.

That's to provide room for the Z-axis assembly although they are much further than necessary in the photo. I adjusted them later (more photos will be uploaded shortly).

I'll try to cut as slow as possible for my first cuts but if the flexing is more than I can bear, then I'll switch out the threaded rods for 8mm ones.
The idea is to use this first crude set up to cut some neater more accurate MDF pieces for a smaller Z - axis assembly. If this can just hold out long enough for that, I'll be golden.

The problem with a sealed box and no vacuum (or compressed air,) is that the chips you're cutting will just pile up on what you're cutting and cause lots of problems if they aren't cleared away frequently. When cutting wood you can easily start a fire.

I'm still not set on the sealed box. I know chips will build up on the rails and probably bind up the axes if nothing is done about it for a long time on long jobs; perhaps I could attach a small fan to one end of the box and a vent to the other to direct the dust outside the building. I'll keep thinking in that regard.