China cnc controller “scale” ratio issue

[JP foodtrucks]

We currently have a Chinese plasma cutting machine controller, table, and torch with a model number of SH-2012AH-QG, “Unich” LXP1325, hau rong welding LGK7-63 respectively.

I am having trouble making the cnc controller output cuts to the desired 1:1 unit scale.

additional facts that may help understanding the problem;

-When cutting a test line of 94in (2387.6mm) the table controller requires a "scale" value of approximately .338 to produce a true metal cut length of 94in (2387.6mm)
-With the .338 "scale" value selected the travel value in the machine controller is reflects 31.77in (807mm)
-The Cam software is FastCam v7, using the "start" post-control-processor during computer installation
-Upon use the table, controller is reset to factory parameters using "GG3" on the start screen.
-The microstep THC is working well and the plasma machine is striking an arc and cutting through metal with proper height control creating a good finish.
- the “golden ratio” of .338 is producing parts close to tolerance (~.250)
I know support isn’t great for these machines and Im awaiting a return email from the microstep control manufacturer.

Anyone shed some light on my problem?

[acourtjester]

Your machine is setup in metric, I would look at the software to see if there is a selection between inch and metric. Mach has that if so just change the setting.

inch.JPG

[JP foodtrucks]

The cnc controller is in metric at the moment but the g code is also in metric. Fastcam puts out code for the “start” post processor control in metric I assume.

Changing the machine to imperial has made no difference, in fact that make the table axes unmovable and a terrible overdrive noise comes from the motors.

[acourtjester]

Ok there is a command in the G-code that states inch or metric, you can look at the g-code to see which is set then find out how to change if needed.

inch.JPG

[tcaudle]

sounds like maybe the steps per unit (calibration) are off. Having to fudge the rationj which should be .3937 is saying its traveing further each step than it should . There should be some way to change the calibration If you want o know what it should be then run a "ruler test". There is a calibration calculator at https://www.candcnc.net/knowledgebase/m ... alculator/.

Go to the Fine Tuning (green ) section . It asks you to unput the steps per unit (in inches or mm) and a test move and then ti will tell you what the new steps value should be . Do it all all of the axis

[JP foodtrucks]

It was the Numerator/denominator parameters in the system setup of the cnc. That’s how’s the stepping motors are tuned. Thanks all

[Daniel Alstott]

What did you end up with for your settings just curious