DM 2800 gets fitted with EMC2

[UWP_Wes]

Well it took about a year, but I think I can finally call it done. I'm not sure if I would do it again, but I did it once!

This is a Dyna Mechatronics 2800 mill. It originally had the SKIP control, but I found it very limited. Soon after buying it I decided to convert to EMC2 controls.

The mill was very lightly used. The shop I bought it from used it to make graphite electrodes for an EDM machine. I have a copy of the original invoice which shows that it cost almost $30,000 for the package circa 1992!

I chose to replace the stepper drivers with Gecko 201 drives to get rid of the horrible cogging sound the machine had at low speeds. Soon after getting the machine moving with the Gecko drives, I had an electrical "issue" which resulted in me losing the stepper power supply, D/A board, and spindle motor drive.

I was unable to find a new spindle motor drive (170V BLDC) so I chose to retrofit a 3PH AC motor with a VFD. This presumably gives me much more low-end torque. As you might know, there is almost no room to shoe-horn an AC induction motor in where the old DC motor fit. So I set out to find a 1KW AC induction motor, with the smallest outside diameter and lightest frame I could get. I scored a .75kW Baldor motor on eBay and called it good enough. I had to make a custom motor end plate (whatever it is called that the bearing goes in). I also had to modify the tensioner because I had increased the center distance. This led me to swap the cone pulley arrangement to timing belts to avoid having to move the motor so much to tighten the belt. The final clearance was about 3mm on front and back of the motor .
(BTW I DO NOT recommend that ANYONE try this spindle motor retrofit. It was a pain)

Now I have the machine running EMC2 with max feed rate of 2400mm/min (about the same as it had before). I also have full CNC control of the spindle, including reverse (not like I need it, but I have it anyway). There are two sets of timing pulleys. This gives me 1:2 and 2:1 ratios, so I have 0-2000 RPM in low range, and about 500-8000 RPM in high range.

Almost none of the original electronics were reused. I have most of the old parts if anyone is interested. (spindle motor, stepper drives, new D/A board, contacter, control panel, main dist. board, DC injection brake, brake power supply, etc).

-Wes

[Fastest1]

Good work. I used a Bardac 1600i to control the spindle motor on my lathe. Originally the motor was 140vdc. I think the Bardac with a 120v input only puts out a 90 vdc however it gives me the rpm I request. If I moved up to a 220 input I could get up to a 180vdc output (output is adjustable). It will allow dual vlotage input. Anyway nice work.

[davidponte]

Hi
you are putting the parts for the dyna myte 2800 for sale? what do you want for them?

[UWP_Wes]

David,

I sent you PM.

All the old parts are available. I might even sell the whole machine for the right price.

I have switched the machine to Mach 3 due to some PC issues (video card). It is running great.

Wes

[2ferrous]

Here is the PDF of the BT30 pull stud.
However I'm not sure the drawing is entirely correct.
The pull studs I have, which came from Dyna Mechtronics, are 45deg.
You might want to compare the drawing to the studs you have.

Timothy

[rickster58]

I also have a DM 2800 with the 10,000 rpm spindle. The machine is pretty awesome for what it is. Does anyone know the part number of the belt? Mine has a three step pulley.
Rick<><