Problem going to start point - Pirate4x4.Com : 4x4 and Off-Road Forum

jduck · 06-05-2010, 01:50 PM

I cut about a dozen parts and then I loaded a different program. This one is supposed to start at x8,y8 but when the program starts it jogs to x8,y4. If I load a program that starts cutting at 0,0 it runs fine, but all the programs that its supposed to jog to a point on the table the y axis goes half of what its supposed to. It cuts the rest of the file correctly but is 4" lower on the sheet of steel than supposed to be. I checked all the set screws and everything is tight. Any ideas?

jduck · 06-06-2010, 05:08 AM

Any suggestions on what to check? As far as I know nothing changed in the set up of the controllers, the belts are good, gears/rails are clean...not sure what else to look at. The green light on the control box stays lit up but it dosnt move. All the plugs are tight and clean...I would think the control box or a motor was acting up but it only does it at the beginning of a file when its supposed to start in the middle somewhere.

cj5 buggy · 06-06-2010, 05:19 AM

few pics on what we are working on.

Testing and all was well.

picture of the thin metal testing on the rock.

This is what we need to finish.

HardcorewannabeXJ · 06-07-2010, 07:43 AM

If it's cutting out the correct shape in the wrong place, this would be High Speed Position loss. As the stepper motors turn faster, they have the least amount of power. In between all cuts, the machine moves at it's Maximum Feedrate in order to shorten the program time as much as possible. The default value is 300 inches per minute. On a good smooth running machine, the motors are perfectly capable of achieving this speed. If the motors have to push through excess resistance, you probably won't be able to achieve 300, which is why we typically set the maximum feedrate to 225-250 ipm.

If the gantry is not square on the table, this will cause some resistance, as well as the gear being too tight in the gear rack possibly supporting the weight of the table. Things along those lines.

I would check your Maximum Feedrate and set it to at least 250, then mark your 0,0 position and run a dry run. If it comes back to the same exact point it started, then it didn't loose position and you should be good to cut it out.

jduck · 06-07-2010, 07:01 PM

Quote:

Originally Posted by HardcorewannabeXJ

If it's cutting out the correct shape in the wrong place, this would be High Speed Position loss. As the stepper motors turn faster, they have the least amount of power. In between all cuts, the machine moves at it's Maximum Feedrate in order to shorten the program time as much as possible. The default value is 300 inches per minute. On a good smooth running machine, the motors are perfectly capable of achieving this speed. If the motors have to push through excess resistance, you probably won't be able to achieve 300, which is why we typically set the maximum feedrate to 225-250 ipm.

If the gantry is not square on the table, this will cause some resistance, as well as the gear being too tight in the gear rack possibly supporting the weight of the table. Things along those lines.

I would check your Maximum Feedrate and set it to at least 250, then mark your 0,0 position and run a dry run. If it comes back to the same exact point it started, then it didn't loose position and you should be good to cut it out.

This worked..I set it to 250 and it did the same thing, so I went to 200 and it ran fine. Now I need to figure out where/why its binding. I assume its square, when its jogged to the end of the gear rack both pinion gears are at the same spot on the gear racks. Any tricks on setting the the gear tightness? Thanks for your help!!!

HardcorewannabeXJ · 06-08-2010, 07:53 AM

Quote:

Originally Posted by jduck

Any tricks on setting the the gear tightness? Thanks for your help!!!

Start at one end of the table, and wiggle each end of the gantry back and forth to check for any backlash. If there is none, check the weight supporting CAM followers and see if they are free spinning. If they are free spinning, the closest Gear is too tight in the gear rack and is actually supporting the weight of the gantry, which is bad. Move the gantry a foot down the table and repeat. This test will tell you how your gear is meshing over the whole length of the table, you may find high and low spots where the gear RACK will need to be adjusted to make it parallel with the rails.

06-05-2010, 01:50 PM	#1 (permalink)
jduck Registered User Join Date: Feb 2004 Member # 26935 Location: Athens, GA Posts: 573	Problem going to start point I cut about a dozen parts and then I loaded a different program. This one is supposed to start at x8,y8 but when the program starts it jogs to x8,y4. If I load a program that starts cutting at 0,0 it runs fine, but all the programs that its supposed to jog to a point on the table the y axis goes half of what its supposed to. It cuts the rest of the file correctly but is 4" lower on the sheet of steel than supposed to be. I checked all the set screws and everything is tight. Any ideas?

06-06-2010, 05:19 AM	#3 (permalink)
cj5 buggy Semper Fi Join Date: Aug 2004 Member # 34606 Location: Hardeeville, SC Posts: 1,084	few pics on what we are working on. Testing and all was well. picture of the thin metal testing on the rock. This is what we need to finish. __________________ Frank 49, 55, 57, 58, 75, 80, 93, 02, 07, and still growing check out our 68 charger build http://www.pirate4x4.com/forum/showt...7&highlight=68

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06-06-2010, 05:08 AM	#2 (permalink)
jduck Registered User Join Date: Feb 2004 Member # 26935 Location: Athens, GA Posts: 573	Any suggestions on what to check? As far as I know nothing changed in the set up of the controllers, the belts are good, gears/rails are clean...not sure what else to look at. The green light on the control box stays lit up but it dosnt move. All the plugs are tight and clean...I would think the control box or a motor was acting up but it only does it at the beginning of a file when its supposed to start in the middle somewhere.

06-07-2010, 07:43 AM	#4 (permalink)
HardcorewannabeXJ Registered User Join Date: Jan 2007 Member # 84593 Location: Reno, NV Posts: 3,004	If it's cutting out the correct shape in the wrong place, this would be High Speed Position loss. As the stepper motors turn faster, they have the least amount of power. In between all cuts, the machine moves at it's Maximum Feedrate in order to shorten the program time as much as possible. The default value is 300 inches per minute. On a good smooth running machine, the motors are perfectly capable of achieving this speed. If the motors have to push through excess resistance, you probably won't be able to achieve 300, which is why we typically set the maximum feedrate to 225-250 ipm. If the gantry is not square on the table, this will cause some resistance, as well as the gear being too tight in the gear rack possibly supporting the weight of the table. Things along those lines. I would check your Maximum Feedrate and set it to at least 250, then mark your 0,0 position and run a dry run. If it comes back to the same exact point it started, then it didn't loose position and you should be good to cut it out.