[somebodyelse]

Hi,

This is my first time learning about motion controllers, I need to upgrade my machine, I think this is where I need to upgrade next.

I work for a large company with a small CNC shop in the back for prototyping and R&D style projects. We recently upgraded our CAM package from BobCAM to SolidCAM 3D iMachining and 4th axis, and now that I am not limited by our CAD CAM setup, I am finding limitations in the code I can safely feed our machine.

For example, the G code for a helical plunge will result in an arc cut on the XY plane followed by a Z rapid plunge. I experience pauses between lines of code etc resulting in poor surface finish. I am planning to keep our baby Bridgeport, it has enough work envelope and the accuracy is enough for my work, RPM's are ok, and the torque is sufficient. But the CNC part drives me nuts, the inch per minute while cutting an arc is never correct, it pauses at the worst times. I can list many other problems but enough of my ranting. :violin:

Current Setup:
SolidCAM for tool paths
MicroKinetics CNC Express XL (MILL)
4th Axis rotary table (I use it for simultaneous)
Mill uses Stepper motors not servos (all open loop system)
Windows XP laptop (off network and dedicated to running the mill only, no MP3's here lol)
MillMaster 2014 (Microkinetics proprietary control software running on the laptop)
TECO 7300CV variable frequency spindle controller (USB)
MN400 Motion Controller (interfaces between PC and stepper drivers)
DM8010 Stepper drivers (1 for each axis, 4 total)

Our machine is fairly accurate, I can achieve accuracy within 0.0005" when it matters, and backlash is about 0.002-0.003 depending on which axis.

Our budget is basically whatever is justifiable, I'm thinking less than 5K. We don't want to waste 5K if little difference will be noticed after 1K, and we don't want to spend 1K if we could get something much better for 4K.

What would you change, and what would you change it to??:drowning:

[Jon.N.CNC]

Wow 5k!, you could replace all your motors for a closed loop pro servo system on ac drivers hell you could probably squeeze in a ups and new pc.

But some of the issues don't really ring true to being solely a motion controller issue, does the machine return to zero after these unexpected moves?

Also what spec is the pc? I use both Mach 3 and uccnc and both with xp spec machines have struggled to keep the motion controllers buffer at a good level, or in other words fed with commands which can and did cause unexpected pauses for me.

[somebodyelse]

Wow 5k!, you could replace all your motors for a closed loop pro servo system on ac drivers hell you could probably squeeze in a ups and new pc.

But some of the issues don't really ring true to being solely a motion controller issue, does the machine return to zero after these unexpected moves?

Also what spec is the pc? I use both Mach 3 and uccnc and both with xp spec machines have struggled to keep the motion controllers buffer at a good level, or in other words fed with commands which can and did cause unexpected pauses for me.

I have had issues before with the machine missing steps, that had to do with mechanical issues, bearing failure, gibbs over-tightened etc. The odd behavior i'm referring to is definately not mechanical or related to the motors missing steps, I believe its on the PC side because the machine can return to zero after, once after giving it a home command it skipped retracting the Z axis to its standard height and just snapped the tool off (normal behavior is home Z, then Y, then X). The fix for this problem is when the frequency of paranormal activity increases I reinstall the software on the PC and all is well for months to come. PC is a Laptop (dell) Intel core2duo 2.0GHZ 1GB Ram. Running XP SP3, no extra frills installed, no internet ( I do have an ethernet cable for file transfer only but no internet or real networking ).

We want to stick with the stepper motors we have instead of switching to closed loop for now, it really hasn't proven to be a limitation for us as of yet, the machines rigidity causes problems before i hit the force threshold where steps are missed.

I see what you are saying about feeding the buffer, that could be the case here, but if it is I wouldn't know how to be sure its the PC and not the software running on it (maybe Mach3 would operate faster? or If its PC then both would be equal?)