Messages

1

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 30, 2012, 11:18:55 AM »

1182.change for the x-axis
1183.change for the y-axis

It doesn't make sense since they are the same pitch & belt drive but maybe since the y-axis has to move more weight (the entire table + x-axis motor mount and servo) it's steps are fractionally smaller?

Sebastian

2

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 27, 2012, 09:50:01 AM »

It's fixed!!

So last night the first thing that I did was use the drivertest s/w to see how much I could increase the output frequency. My computer was given the green light to 100K but I decided to try 45K first and increase the step/dir to 10us. I then put my dial indicator back in place and ran the set axis one more time to see if they were still within 0.002mm and they were so I decided to make one test cut before changing to Hood's calculated settings. The circle was cut perfectly. At that point I decided to leave my step settings as they were and cut the horseshoe part, and it cut perfectly as well. I did a couple more test cuts at 10mm cut depths and higher speeds and everything always measured up so it seems my problem is fixed!!

Thanks for all the help guys, I still don't understand if it was increasing the freq to 45 or increasing the step/dir time which solved the problem but I don't want to figure that one out now that it's cutting as it should

Cheers,
Sebastian

3

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 26, 2012, 02:01:23 PM »

Canada eh! I grew up with the metric system, but all of the cutters are imperial and are generally produced in the states. Metric ones are possible but then it's hard to find metric collets etc... Just easier, cheaper and more selection in imperial cutters over here. Some machinists here work in imperial for travels, cuts etc... but that just doesn't make any sense to me.

Sebastian

4

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 26, 2012, 01:44:07 PM »

Yes I agree with you on the tweaking, that's just masking the problem and probably wouldn't work.

Sebastian

5

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 26, 2012, 01:26:28 PM »

No I'm currently at work, will set it to that first then cut the circle with the posted g-code and see the result.

Can you verify that the gcode is fine?

If it's too small/big, should I manually adjust the steps? For example too big -> reduce steps, to small -> increase steps

Sebastian

6

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 26, 2012, 12:30:54 PM »

Okay this is my idea of a game plan for tonight:

Brand new 3 flute 0.5" carbide ZRN coated bit (should be delivered today, says enroute)

Cut a 30mm circle with the following code that was generated by the Mach3 wizard:

F400
G00 Z10
G00 X8.55 Y0
G00 Z1
G01 Z-0.5 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-1 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-1.5 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-2 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-2.5 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-3 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-3.5 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-4 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-4.5 F50
G02 X8.55 Y0 I-8.55 J0 F400
G01 Z-4.9 F50
G02 X8.55 Y0 I-8.55 J0 F400
G00 Z10
G00 X8.65 Y0
G01 Z-4 F400
G01 Z-5 F50
G03 X8.65 Y0 I-8.65 J0 F400
G00 Z10
G00 X0 Y0
M30

Attached a pic below of the screenshot. Should I adjust my steps manually until this circle is exactly 30mm?

Then cut a 30mm profile circles with Solidcam gcode. If same size, then cut teh horseshoe?

Sebastian

7

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 26, 2012, 12:15:12 PM »

The horseshoe is the solid material left, revised pic.

Sebastian

8

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 26, 2012, 12:11:51 PM »

My solidcam code test has been a horseshoe type shape as shown below. This allows me to pocket, lift z, lower z, and finish in one pass.

My plain circles have been generated by the mach3 cut circle wizard.

Sebastian

9

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 26, 2012, 11:32:46 AM »

One more thing, should I turn off "Enchanced Pulsing" or increase/reduce the step & dir time in the motor tuning window?

Sebastian

10

General Mach Discussion / Re: Cut parts are wrong size, CNC knee mill problem

« on: July 26, 2012, 11:30:22 AM »

1000 line encoders
5TPI ballscrews, 0.2"
The number is somewhere around 1179-1184

The problem is that it cuts the inside too small now and the outside too big. The only way to fix it is to reduce the cutter diameter by 0.2mm in the solidcam. Because if I decrease the steps per mm, then the outside will be to size the inside will be even smaller. If I increase the steps per mm, then the inside will be fine but the outside will be too large. If the outside was too big and the inside was too big, than that would indicate that the steps per mm was off. It's hard to explain, but do you sort of understand what I was trying to say?

Sebastian