Concrete VMC

[lukahr]

I bought my spindle cartridge from aliexpress almost 2 years ago, the same seller is still active and he sells them a bit cheaper now.
https://nl.aliexpress.com/item/32397...27424c4dhHklQa
The servo is from szgh automation also from china. I ordered a 12krpm version after having contact with them they make servo's to your own specs.
https://www.szghauto.com/product/115.html

Stef

Thanks for links.
It looks like cartridge is on sale right now 50% off 550€ including shipping is really good price. Is possible to upgrade cartidges like this for faster rpm as i see that max rpm is only 6000 it would be nice to match servo rpm


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[mick41zxr]

I have the same spindle, I rebuilt it with precision angular contact bearings & kluber grease.
Will hold 8k rpm (spindle max) sustained with relatively little temperature rise.
Rebuild is easy to do if you have access to a press & heat gun, just make sure you have matched sets of bearings.
Regards,
M

[Azalin]

What kind of belt/pulley is used on the spindle?

Thanks

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[mick41zxr]

T5 x 16mm

[stef110]

Its a HTD5 beld which is 20mm with and there are 2 on the spindle.

About the bearings i didn't look in to that but will do it later for now i want to use it at 6000rpm.

Last weekend the steel work for the enclosure arrived, and the steelwork for the toolchanger.
The base of the enclosure is made from 2mm stainless steel which is bend in to shape. I need to weld it to make it a water tight base for the enclosure.
There will be drains on each side that will transfer the coolant back to the main tank that will come under the base of the machine.

Stef

[daniba73]

Hi, fantastic cnc!
Did you have difficulty calibrating the Delta servos?

[Myrestam]

Nice build! Do you have any idea how much you spent on it so far ?

[klaas123]

A bit too late for you Stef, but I just saw this video of Stefan Gotteswinter showing how he trammed his mill with soft copper and epoxy:

[klaas123]

Stefan has posted many more interesting video's on Youtube: https://www.youtube.com/user/syyl/videos

[stef110]

I haven't looked in to the servo tuning yet, out of the box it already runs nice.
Total cost's right now is somewhere around 15-16k euro didn't keep track of all the small orders.
I had seen Stefans movies before from him i get the whole epoxy tramming idea but i didn't want to lift the whole column and head at 450kg and than only have one hour to tram everything.
I made a wrong judgement call on the epoxy injection and i learned from that and in the end it will be fine luckily.

Stef

[klaas123]

Yes, I understand Stef, with that amount of weight you would probably run out of time. Another option could have been to use 5mm thick softened copper, tram the mill and then fill up with epoxy.

[pippin88]

I think for a new build (not fixing up a manual machine like Stefan), the best way is to integrate in injection points / passages for use when epoxy tramming.

Have set screws as well as the hold down bolts.
Use a compressible gasket
Tram using set screws and hold down bolts (done up lightly)
Then inject epoxy through a few holes you integrated for the purpose
Wait for epoxy to cure
Tighten down bolts fully

[daniba73]

@stef110


I also own your servo kits. I did auto tuning. I had difficulty in synchronizing the axes. as a check you can try cutting octagon and measuring diagonals.

[stef110]

@daniba73 Did you had these synchronizing error before or after tuning?

This weekend welded the bottom of the enclosure, machine becomes pretty big!
I gone mount a mist coolant on the head now first so i can start machining my atc parts and when the atc are done, i gone order the rest of the sheet metal for the rest of the enclosure.
I also temporarily mounted the control panel above the machine so i can easily control the machine now

Stef

[daniba73]

Hi,
I didn't try without automatic calibration, I thought it was a necessary practice.
P.S I'm designing a VMC very similar to yours.
I was thinking of using cement (with special characteristics) instead of epoxy granite.
I'm Italian, the post I opened can be seen here: https://www.cncitalia.net/forum/view...78526&start=15

[daniba73]

question:
the welded parts, have you not subjected them to thermal distension?
it's a very important phase!
internal tensions are created by welding.
with changes in the outside temperature, these voltages change.
consequently they change shape.
changing shape, it compromises stability and precision.

another question:
Do the protections you used go well with an emulsion jet?
under the metal blades, is the sheet present to make the cover waterproof?

[stef110]

The x axis sadle have been heat threaded after welding so that one should be perfect.
The head however i didn't heat threaded because the main body is fillet with epoxy so i don't really see that al moving. Its a gamble on my side lets see how it gone turn out.

Stef

[daniba73]

was there a particular reason why you used epoxy instead of anti-retraction cement?

[mchlfranko]

was there a particular reason why you used epoxy instead of anti-retraction cement?

Go back to page 5 (post #53) and start reading from there. Lots of debate on the subject prior to Stef making a decision.

Great job Stef! This looks amazing!

[stef110]

I choose for the epoxy granite, because UHCP also required some special work methods. and there where enough people how said epoxy granite would be better and more stable. So then i just decided to use that.

Today i started the build of the tool changer
Part 1 of atc build is done, the big aluminum support block is done where the linear rails are one. Also welded the mounting arm which turned out pretty beefy. Its made from 100mmx100mmx5mm tube.
Next up is the air cylinder mount and the mounting plate where the linear ways are connected to.