New build a stronger machine for my workspace.

[Clive S]

Alex
You are going to need a much stronger base than 40x40 also it needs triangulation if you want to cut ali also the Z would benefit from linear rails as well. Most of the parts would be better out of 20mm ali and if possible try and go up to a 68V non linear power supply (just check that the drives can handle that)

[Alexandre]

Hello Clive

Yes i need a reinforced base but i only had 40X40 bars( recycled from other machinery). For this reason i use "6 legs" to support the weight of machine. But it is possible that i will place some triangles to reinforce all structure.
Z also have linear rails from THK and ballscrew from NSK, it is a complete "head" dismantled from another machine.
Sure most of the parts are 20mm but there are a few like motor supports and spacers that was not necessary.
What is the difference of non linear power supply and others?

Thanks

[routercnc]

Here is a technical explanation of linear power supply vs switch mode:
https://www.circuitspecialists.com/b...ode-vs-linear/

A linear power supply is often preferred for CNC machines. My understanding is that SMPS can generate more electrical noise (as it is switching currents on and off rapidly), and you don't want stray signals interfering with the drive signals.

Also, as I found out, the linear power supply is relatively straightforward to build, although you need to work out a few things first such as the size of the transformer. But there was lots of help on this site for the specification of the components (have a search for linear power supply build) - obviously you need to be sure of yourself when working with dangerous mains voltages.

[Clive S]

Alex I see its been answered but one of the advantages is the non linear P.S. is that they handle back EMF much better and you can generally use a small amperage one as the caps store the energy. You only need the transformer, rectifier and caps to build one as long as you are happy with handling the mains voltage of about 230V.

[Boyan Silyavski]

Hi Alex,

here are my thoughts:

-For metal milling i would reinforce the whole gantry with a backing plate. for example aluminum 20 or 25mm thick. I suggest to copy aluminum gantry design from the build logs here in forum. Many people here have nice aluminum gantry machines. Just read the logs.

-Square rails 20 size is perfect. 20 size ball screw is too much. 1610 for all axis and 1605 for Z is what most people on this forum use. Fast enough for wood, good resolution enough for aluminum.

-Convert to closed loop later? Not a good idea. Use 500-600w 70VDC power supply, drives Leadshine Am822 with the 3nm motors you have chosen or straight go to 400W servo / 200 would work 1:1.5 or bigger but as there is no price difference../ . its difficult to find a belt size that will fit both motors, pulleys will be different bore, same as motor holes, which would change belt size... / By the way- ball screws driven via short belts /~250-350mm/ is best. 15mm HTD 5 belt, 20t puleys for 1:1

-0.8kw spindle could cut aluminum with 6mm cutter ok at 3mm depth, even at 6mm sometimes. But 2.2kw spindle will be better here. I use for this purpose 3kw, but 2.2 pricewise is best. Anyways 6mm is the most used cutter as not to waste material. For small stuff 3mm. Toshiba VFD drives are better and best priced in ebay from Italy.

-Z100? Not good. At least 150mm i would say. Fixtures, boards, they would eat from the height. Design the machine so that you have 200mm clearance from gantry and Z to table for that 150mm travel. I would sell the Z if 10mm travel and make one from scratch, which will suit 100% what i am doing. As Z is important. Best design is rails and plate to move, not bearing blocks.

-15mm plates from aluminum could bend if long enough. I would use at least 20mm or 25mm. or reinforced with steel. Steel is ~ 3 times stronger, 3 times cheaper and 3 times heavier than aluminum.

-Unsupported aluminum table bed is NOT strong. +Its very expensive. best value is to make a steel table from UPN 100 profile in your particular case. Best is to weld them. Cross table, one next the other... Then drill holes and tap them. It would make your machine very rigid. which is desirable.


In short read some build logs, all the info is there.

[Boyan Silyavski]

By the way have you seen that? Unfinished Project - Fixed Gantry M/C - 500x400x100mm Approx - Cost over £3K in parts

I live in Spain and there are constantly transports going from here and back to UK. Must be same with Portugal. Cause more or less that's the machine for doing aluminum. I would change the Z rails to square supported, but that's not expensive as they are very short. And having in mind that the machine is working already, you could do that as first job.

[A_Camera]

By the way have you seen that? Unfinished Project - Fixed Gantry M/C - 500x400x100mm Approx - Cost over £3K in parts



I live in Spain and there are constantly transports going from here and back to UK. Must be same with Portugal. Cause more or less that's the machine for doing aluminum. I would change the Z rails to square supported, but that's not expensive as they are very short. And having in mind that the machine is working already, you could do that as first job.

Yes, that is definitely a nice machine, even if it is difficult to transport. Anyway, I think he needs something very similar to that, but it does not have the work area he had in mind. It is very similar to what I have designed and built for myself, and the fixed gantry really increases the rigidity as well as it decreases the complexity and to square it is also much easier than a moving gantry type with slaved motors on one axis.