Aluminium Extrusion Router Build

[NFryer]

I've now got the inductive limit sensors mounted for the z and y axes. I've got a 2 core CY cable to supply the power and a 4 core CY cable for the signal outputs. I used a couple of 5 way terminal blocks to connect the power leads of each sensor. I also tested a sensor and it seems to work well on aluminium with the output dropping to 0V when it is approximately 4mm away from it.

I've also got the aluminium profile that I need to build the frame from KJN Aluminium Profiles. They provided me a very good customer and the profile seems to be cut very accurately and pretty much bang on square as well.

Finally I had a bit of a puzzling problem with the Y axis ballscrew. As I was moving the Z axis along it would get harder to move towards either end of the travel. After a bit of measuring and checking I found that the 15mm plate the ballnut mount is fastened to was actually about 15.5mm thick which was enough to cause the problem. I took it apart and skimmed 0.5mm from it around the ballnut mount and put it back together. I tried to put the ballscrew back and found annoyingly that I couldn't. Apart it came again to skim the whole area to the side of the mount to allow the ballscrew to slide in.




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[NFryer]

I've made a bit more progress in my CNC router build, and have made a start in building the basic frame out of 80*80 aluminium extrusion, some simple plates that I made and some 80mm aluminium equal angle. I've also made some simple plates to bolt onto the bottom of the legs to which I can screw in some levelling feet. With the plates I smoothed the edges on a disc sander and gave them a overall sanding with wet and dry sandpaper. Not entirely necessary but they do look neat and a bit shiny.




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[routercnc]

Nice work there !

[CNCKitMan]

tasty mate!

[Nr1madman]

Those are some sexy plates :D

Well done!

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[NFryer]

Just a small progress update on my build, unfortunately I haven't had as much time recently to get on with the build. I have drilled and tapped the plates which have the x axis linear rails fastened to them and started on the x axis end plates which support the x axis ballscrew. On one I still need to rout out the motor mount which will be slightly different than on the original plan as the pulley on the ballscrew is a bit further away from the end plate than I thought it would. I intend to rout out a simple rectangular hole in the end plate and make a 6mm plate with the adjustment slots to bolt to the end plate. I've also accurately measured the cross rails and x axis rails and got some 0.25mm stainless steel shim stock to take up any differences. To get an accurate length I used a shorter length of aluminium profile and measured the difference between it and the piece I wanted to know the length of. That way you don't need to measure the entire length of the profile.




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[NFryer]

Hi everyone, just a quick question regarding the design of the linear power supply for the stepper motors. I'm going with a transformer power supply and know to take into account the mains power supply variations to calculate the DC output but what margin should you leave for the voltage rise caused by the motors back EMF. Also I'm using quite a large toroidal transformer as I've got 4 motors to power, does anybody use inrush current limiting, as there are some nice looking 16A Sedlbauer current limiters on eBay at the moment for £30. Thanks in advance for any help.


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[Clive S]

What size toroidal, what motors and what drives are you using? Too many varables

[A_Camera]

Hi everyone, just a quick question regarding the design of the linear power supply for the stepper motors. I'm going with a transformer power supply and know to take into account the mains power supply variations to calculate the DC output but what margin should you leave for the voltage rise caused by the motors back EMF. Also I'm using quite a large toroidal transformer as I've got 4 motors to power, does anybody use inrush current limiting, as there are some nice looking 16A Sedlbauer current limiters on eBay at the moment for £30. Thanks in advance for any help.


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I am using inrush current limiter, I think it's a MUST have with toroidal transformers. If you have a mains fuse of 16A then you can use that one, but if your mains fuse is smaller then you should use a smaller one.

[NFryer]

What size toroidal, what motors and what drives are you using? Too many varables

Hi Clive,

The drives and motors I'm using are the Leadshine Hybrid Stepper ones, HBS86 drive and 60HBM30-1000 NEMA24 motor. The drive has a maximum voltage rating of 80VDC. The toroidal transformer which I haven't got yet will probably be a 45VAC+45VAC 1000VA one from Airlink transformers. I did the following calculations to arrive at this, and if you see any obvious errors can you tell me.

The motors are 2 phase with a current of 5A per phase so 10A per motor. The motors have 4 power leads which means that they will probably be series wound so I think that the motors will pull approximately a third of the maximum, so about 3.3A per motor. I'm using 4 motors so the total current draw should be about 13A.

For the voltage I took the mains voltage +10% as a worst case so

45VAC + 10% = 49.5VAC
49.5VAC + 4% for transformer regulation = 51.5VAC
51.5 multiplied by 1.414 = 72VDC
72VDC - 2.2V for the bridge rectifier drop gives roughly 70VDC output.

Hopefully this is alright and I haven't made any obvious errors.