Centroid Community CNC Support Forum

Should be able to get it at automotive body shop supply stores, unless no one has auto accidents in NZ.

ashesman wrote: ↑Mon Aug 30, 2021 2:36 am

martyscncgarage wrote: ↑Sun Aug 29, 2021 8:37 am 3M panel bonder. Type used for bonding auto panels.

Thanks, I thought the same as it looks perfect. But I cant find anywhere to buy it here in NZ. Half the country is on lockdown for a while yet! I think it is also only available in tubes that require a special gun and disposable nozzles?

Find a local auto body supply shop and ask for panel bonding adhesive. 3M is not cheap but it's good. I'm sure there are others out there

Brazing would work really nice too with no distortion and little clean up.

polaraligned wrote: ↑Mon Aug 30, 2021 7:29 pm Brazing would work really nice too with no distortion and little clean up.

I didn't even think of brazing or soldering. That's a good idea.

You could run a Buck/boost transformer to get your voltage up for your drives. Might solve your rpm problem, I don't know what your load current is for your drives but the transformers are pretty small and a easy solution. We use them to connect machines on a 208 service that require 230-240V.

Davesvo wrote: ↑Thu Sep 09, 2021 8:11 pm You could run a Buck/boost transformer to get your voltage up for your drives. Might solve your rpm problem, I don't know what your load current is for your drives but the transformers are pretty small and a easy solution. We use them to connect machines on a 208 service that require 230-240V.

Currently I am actually converting it down from 415V to 200V three phase with a 7kVA auto transformer. I have 240V single phase available too but there are still some 200V parts on the machine so I just left all at 200V single phase.

I was more annoyed at paying for motors that were supposed to do what I asked for then didnt!

Its been a while... I decided to take some time off this project as it was starting to frustrate me. Anyways before I did, I did run a test part. Below is a picture of the same part run on the Mazak OEM controller with a program that took its entire 48k memory and one on the Centroid (~1 Mb program). You can see the difference. Although the Centroid program did take about 10 times longer to run The part run on the old controller required a fusion 360 tolerance of 0.5 to make the program small enough to even run.
After a fair bit of testing, I am pretty sure there is something gammy in Centroids spindle encoder zeroing function M150. It means I can never have a safe reliable zeroing of the spindle and reliable orientation controlled by the Centroid PLC (without adding additional position switches and running M150 repeatedly until it works!). I already had one tool change where it oriented incorrectly and mashed the tool rack!

I bit the bullet and bought a Delta C2000 drive and encoder card. Annoying as I already bought a really nice $1000 USD Hitachi SJ-P1 that is awesome all but its inability to do position control on a permanent magnet motor! I really hope the C2000 can run the spindle as nicely as the SJ-P1. Once installed I will remove my orientation code from the PLC and go back to a VFD controlled orientation. At least then it should always stop at the correct position!

I have been tacking away at modifying the machine covers to clear the longer DMM servo motors. Ergh, spray painting, my old enemy!

So, time for another installment... It is riding season so I haven't been doing much.

The Delta C2000 is fitted roughly until I know it works. The encoder card is due tomorrow so keen to see how it all works out.

In my spare time I have been working on my control panel. I suck at sheet metal work so it is slow going for me! A few posts back I put up some pictures of 3D models of what it should look like when I am finished. The idea is to try make it look like the original Mazak control panel, keeping in style with the machine itself. I have come a bit stuck though on how to attach the screen to the inside of the front panel. Ideally it needs to be spot welded but I don't want the welding marks on the outside around the screen. I designed for it to be glued in place but I have tested various glues like JB Weld, Loctite super glue, Wurth body panel glue, urethane windscreen glue, but none of them seem to adhere well enough to the steel. Even if I grind it up roughly! In a previous post someone suggested brazing but I think that heat would still deform the sheet metal.

I welded all the other brackets in place by drilling holes in them and plug welding them with the tig. They left very small marks on the outside, but its on the sides and back so not a problem. Any other suggestions on how to attach these screen brackets would be appreciated.
I am on a mission to finish this machine by Christmas. I have all the parts. Just need to sort that spindle orienting and the control panel and should be nearly there!

3M VHB tape?

ashesman wrote:After a fair bit of testing, I am pretty sure there is something gammy in Centroids spindle encoder zeroing function M150.

Does the problem only show up when the spindle has been running at comparatively high speed?

Try adding logic that ensures the spindle speed is below around 2000 RPM before you call M150.