Varible speed DC Spindle for PCB milling

danimal
Posts: 332
Joined: Wed Mar 13, 2013 5:53 pm
Location: Colorado

Varible speed DC Spindle for PCB milling

Post by danimal » Thu May 16, 2013 7:13 am

So I started on my Variable speed DC spindle today. I am planning on posting a detailed parts list and code later on, but I still have a lot of development to finish for the spindle. I am still waiting on the bearings and spindle shaft to get here, then I need to design the enclosure to accommodate it. Today I just focused on the control system and display. I am not sure how powerful I want to make the spindle, so I decided to start cheap and small and can easily replace the motor and ESC with a larger on if I need to. I have to say that I am kinda surprised at how torquey the motor at this size is. I will go into my design choices a little later.

Image
Shapeoko # 1458

RT0701C Spindle || dual y motor || x axis nema23 with custom carriage 1000mm length || z axis nema23 linear rail upgrade with 1/2-10 ACME

Metroid
Posts: 32
Joined: Thu Mar 14, 2013 12:49 pm
Location: Netherlands

Re: Varible speed DC Spindle for PCB milling

Post by Metroid » Thu May 16, 2013 9:37 am

Hi danimal,

If you have a ESC that is compatible for helicopters, than there should be a governor in the program. You can use this to define rpm's. And if the motor is under load, the speed shall not drop.

Gr. Rob.
eShapeOko #92, 4x Stepper Shield, All in One GRBL
The Wings

danimal
Posts: 332
Joined: Wed Mar 13, 2013 5:53 pm
Location: Colorado

Re: Varible speed DC Spindle for PCB milling

Post by danimal » Thu May 16, 2013 6:10 pm

Metroid wrote:Hi danimal,

If you have a ESC that is compatible for helicopters, than there should be a governor in the program. You can use this to define rpm's. And if the motor is under load, the speed shall not drop.

Gr. Rob.
That is correct, I am using the ESC to control and maintain rpm. The arduino is just modifying the pulse width of the control input to the ESC. It is powered just like in a helicopter, but is getting the armed signal and rotational PWM from the arduino.
Shapeoko # 1458

RT0701C Spindle || dual y motor || x axis nema23 with custom carriage 1000mm length || z axis nema23 linear rail upgrade with 1/2-10 ACME

danimal
Posts: 332
Joined: Wed Mar 13, 2013 5:53 pm
Location: Colorado

Re: Varible speed DC Spindle for PCB milling

Post by danimal » Thu May 16, 2013 6:12 pm

And actually it is underpowered in this video and only is reaching about 8800 rpm. I am still waiting on my 12v supply to get here for full power testing.
Shapeoko # 1458

RT0701C Spindle || dual y motor || x axis nema23 with custom carriage 1000mm length || z axis nema23 linear rail upgrade with 1/2-10 ACME

Metroid
Posts: 32
Joined: Thu Mar 14, 2013 12:49 pm
Location: Netherlands

Re: Varible speed DC Spindle for PCB milling

Post by Metroid » Thu May 16, 2013 6:41 pm

It's the same idea that I've got for my spindle. I have to wait for the mounting brackets for the motor and ER11 collet with 8mm shaft. http://www.ebay.nl/itm/111056518144?ssP ... 1436.l2649
The motor will be 24V and about 32A. A total of 768W x 85% = 652.8W on the spindle, more than a Dewald or Kress. Turning speed max ~22000 rpm.

Gr. Rob.
eShapeOko #92, 4x Stepper Shield, All in One GRBL
The Wings

Robump
Posts: 3
Joined: Wed Apr 03, 2013 6:24 am

Re: Varible speed DC Spindle for PCB milling

Post by Robump » Thu May 16, 2013 8:09 pm

Looks good... Looking forward to a guide/instructions!

danimal
Posts: 332
Joined: Wed Mar 13, 2013 5:53 pm
Location: Colorado

Re: Varible speed DC Spindle for PCB milling

Post by danimal » Fri May 17, 2013 8:34 am

Metroid wrote:It's the same idea that I've got for my spindle. I have to wait for the mounting brackets for the motor and ER11 collet with 8mm shaft. http://www.ebay.nl/itm/111056518144?ssP ... 1436.l2649
The motor will be 24V and about 32A. A total of 768W x 85% = 652.8W on the spindle, more than a Dewald or Kress. Turning speed max ~22000 rpm.

Gr. Rob.
What bearings did you go with? The only angular contact bearings I could find that would handle that rpm were about $60 - 100 each. I went with some ABEC 5 rated angular contact bearings that should be pretty good, but they are only rated for about 16000 rpm so I had to limit my spindle speed to a little under that. The motor that I have is a 12V 30 amp DC outrunner with a voltage constant rating of 1100kv. I went with the outrunner due to not wanting to develop a cooling system for the inrunners. I see that there are a lot of them out there, but being that the outrunners are self cooling I figured it would simplify everything a little. I bought a ER11 Collet with a 12mm shaft from the same manufacturer, so I hope that their listed tolerances are correct.
Shapeoko # 1458

RT0701C Spindle || dual y motor || x axis nema23 with custom carriage 1000mm length || z axis nema23 linear rail upgrade with 1/2-10 ACME

danimal
Posts: 332
Joined: Wed Mar 13, 2013 5:53 pm
Location: Colorado

Re: Varible speed DC Spindle for PCB milling

Post by danimal » Fri May 17, 2013 5:30 pm

I received my spindle shaft and collet today as well as the bearings that I ordered. I can finally start taking measurements and putting everything together. Just for reference I found this little video for installing angular contact bearings in different configurations. This is the manufacturer of bearings that I chose to buy, they seemed high quality and I know we use them on all the pumps at my work because they are reliable.

http://www.youtube.com/watch?v=Z_vamfXL1fU
Shapeoko # 1458

RT0701C Spindle || dual y motor || x axis nema23 with custom carriage 1000mm length || z axis nema23 linear rail upgrade with 1/2-10 ACME

Metroid
Posts: 32
Joined: Thu Mar 14, 2013 12:49 pm
Location: Netherlands

Re: Varible speed DC Spindle for PCB milling

Post by Metroid » Fri May 17, 2013 10:05 pm

I did not think about that yet. Found some normal ballbarings that are used in my hobby. These have to take both the radial as axial load. To drive a methanol engine (16000 rpm, 1.6hp) or edf 628ZZ, 608ZZ or similar ballbarings are used.

Gr. Rob
eShapeOko #92, 4x Stepper Shield, All in One GRBL
The Wings

Enraged
Posts: 230
Joined: Mon Apr 09, 2012 8:29 pm

Re: Varible speed DC Spindle for PCB milling

Post by Enraged » Fri May 17, 2013 10:38 pm

I was actually just researching this idea. I have a spare Arduino that I wanted to use to control an ESC, controlled either manually, or with the spindle output from Mach3.

Post Reply