Messages

1

General Mach Discussion / Re: Gear Reduction question.

« on: November 17, 2017, 12:42:08 PM »

Worth giving those DMM's a look.
The concept of this machine is to mimic (as close as you can) a hydraulic piston operated press.
The peak current (max load) comes into play at the coining stage when your piston or in my case the screw runs
into the bottom of the die. Stalling at this point cannot happen , The idea would be to hit max peak and stop. Then
that is what the machine would be rated for tonnage. That little 1600oz stepper stopped and stalled at 1.0ton. Not nearly
good enough.  If the DMM servo's frame is equivalent in size to Nema-34 I will definitely consider them.

Quick look at the 1.8kw motor and the frame size is 130mm , I would have to really hack the frame up to shoehorn that motor in.

2

General Mach Discussion / Re: Gear Reduction question.

« on: November 17, 2017, 09:19:33 AM »

Budget limitations at this point means that any change to the motor configuration would need to be "plug and Play"  meaning no changes to the controller
step and direction and Nema-34 frame size only. The Clear Path servo motor may be the only viable option to gain the extra torque. I agree looking at the specs the DMM
servo would be the better option but at this time I'm either going with the Clear Path servo motor or 2 hi-torque steppers. I measured the tonnage last night with a load cell and I'm at exactly 1-ton and need to be at least 2.5 ton to get the desired results and material thickness range. That's with one Chinese 1600oz stepper at 6:1 gear reduction and I needed to slow slow slow it way down to get that 1.0ton load pressure. looks like the torque range is peak till about 125rpm at 12nm on those CP servos. I'm going to get a quote from them later today.

3

General Mach Discussion / Re: Gear Reduction question.

« on: November 16, 2017, 05:01:48 PM »

So looking into the servo options. I have some experience retrofitting a laser system with ClearPath motors and looking at there SD Nema-34 motor the torque spec looks like
its peak is at the RPM were I'll be happy with the speed of the machine. This is roughly the same cost as adding the Hi-torque steppers and additional bits. Here is the data from there site.
I like that these motors are so quiet too.

https://www.teknic.com/model-info/CPM-SDSK-3441S-RLN/

4

General Mach Discussion / Re: Gear Reduction question.

« on: November 16, 2017, 12:19:45 PM »

Hi , Thanks for the replies.
Current set-up is 6:1 gear reduction with 1600oz Nema 34 @ 75vdc. I was looking at the Screw jack with the single input shaft and thought what if ?
So I contacted Joyce Dayton and the friendly customer support guy said that I can remove the single input shaft and make my unit a double input shaft.
Now if I go with two HI-torque 1841oz Nema-34 steppers with 6:1 gear reduction that's twice the HP I may get the desired results (speed and power)
The addition of the two new steppers , another 80vdc power supply and one more stepper driver along with the Screw jack mod and coupler I'm looking
roughly $700 extra dollars.  Its a tough decision but I think this should do the trick.

Not sure why the pic is rotated , sorry.

5

General Mach Discussion / Re: Gear Reduction question.

« on: November 15, 2017, 07:47:07 PM »

Quick Update on the press build. Sorry its been awhile. So many other projects.
So after a lengthy build I attached the coupler to the  1600oz Nema 34 stepper and attempted to bend a 1.0in wide 16gage mild steel piece of material 90 degree.
The machine drives smooth and accurate but when it came to the actual grunt work of getting the tight radius in the bend it stalled and the stepper skipped steps. (big problem) !!!
I have heard of high torque steppers that have as much as 1800oz torque but I'm not sure this is my answer. ? I lowered the motor tuning velocity and accel to the min for max torque and
the results were better but not worthy of calling this machine a press. The downside to the settings change was a predictable slow as molasses pace.
I'm hoping someone has some insight or suggestions here please.   Hi-Torque ? Servo or DC motor , still needs to be programmable. Hoping to stay with the mach3 software as I'm really found of it now.

Thanks in advance.
Dennis

6

General Mach Discussion / Re: Gear Reduction question.

« on: October 06, 2017, 02:09:26 PM »

Eventually that is the plan. I'm new to Mach3 so maybe someone could point me in the right direction regarding these features of changing the speeds using I/O.
The press screw jack has 19.0" inches of travel , I'll only be using 8-10 inches of that travel. So retracting at a higher speed would be very desirable.
Couldn't I just write the federate into the NC code for the stroke ? like G0 (rapid traverse) ?

Thanks
Dennis

7

General Mach Discussion / Re: Gear Reduction question.

« on: October 06, 2017, 10:09:09 AM »

I actually do have inventory to try , located 80vdc 6amp supply.
The Joycedayton screw jack specs:
Screw Dia:1.5" Not ACME actual ballscrew and Nut.
thread picth:1.0"
Grear Ratio : 6:1
worm shaft turns for 1.0"  = 6turns
This by no means will be a quick press , My target was 3Tonnage , I would be happy if this setup yields 2T.
Ideal speed 10ipm , realistic will likely be in the 5-7ipm ?

I appreciate everyone's input.

Thanks
Dennis

8

General Mach Discussion / Re: Gear Reduction question.

« on: October 06, 2017, 06:56:19 AM »

Thank you for this input. I currently have a 15amp 24vdc supply source at the stepper driver. What your saying is go to say a 48vdc supply voltage and I can achieve more RPM's and torque ?

Cheers.
Dennis

9

General Mach Discussion / Re: Gear Reduction question.

« on: October 05, 2017, 07:01:15 AM »

Craig,

Thank you for the very informative response. 2500lb's should do the trick , I was hoping to achieve 3T , but this powers the pursuit anyway. I will continue the build.
I was playing around with Mach3 last evening and it was difficult to find to the sweet spot of speed and torque without loosing steps. Has anyone played around with the
HT (High Torque) Nema-34 motors , I could boost the tonnage slightly with 1800+oz motor. running the servo drive at full current really got the motor hot !! little concerned
about that ?
Thanks again for your quick response.
-Dennis

10

General Mach Discussion / Gear Reduction question.

« on: October 04, 2017, 07:53:17 PM »

Hi ,

Trying something new , Mach3 controlled single axis (Nema-34 1600/oz) Press.
I thought with all these extra parts I have laying around I would try to fabricate a stepper driven press. Unlike most using the HF 20ton H-press/bottle jack method
I would try driving a 5-ton screw jack w/gear reduction. Using a 15amp 24vdc power supply and DQ860MA microstep driver running full 7.8amps I just need to drive this
single axis a few inches up/down and get enough tonnage to bend 16ga mild steel.  My problem is the screw jack has a mighty 6:1 gear ratio and the screw needs to spin
16 revs to equal 1.0inch.  This is where things get sketchy for me. So I figure the steeper motor would need to spin 96 revs to move the screw one inch. Thats ok but I'm new to mach3
and stepper drives , I'm looking for advise on what would be the best and most accurate way to figure out what would give me the most torque and get the desired accurate displayed motion.
My drive can run bewteen 400 and 51200 pulses/rev.  Thank you in advance.