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SW flat length not agreeing with Fasti Folder flat length.

Question asked by Pete Peters on Oct 21, 2014
Latest reply on Oct 24, 2014 by Pete Peters

I’m having an out of spec issue between my Fasti GPI: Graphical Programming Interface vs. SW DRW.

Our Hi-Definition Plasmas can only hold precision @ 0.00 places, with a tolerance spread of ~ 0.040 thousandths.

As long as my SW Flats and the Fasti FLATLENGTH agree within that zone, we fold it.

As long as we use simple outside surface OD: Outside Dimensions, this works great across the entire gauge spectrum.


In this scenario, SW says 23.132 inches wide (DRW Zone: D2) while Fasti PARTLENGTH says 23.015 inches wide (Fasti Screen-Cap), a difference of 0.117 inch (2.9 X our current tolerance)

It is useless to try and fold that.



                                                       Fasti Screen-Cap



My gut is telling me it’s due to the way I am dimensioning the 2nd & 4th legs in the SW DRW.

For folding, the rules are to use “outside surface” or OD dimensions, but I can’t do that here.

The 1st 2” OD leg dim is just fine because it comes from an end and a VS: Virtual Sharp on the outside surface.

The 2nd 2.074” 2VS: Two Vertical Sharps dim uses the top apex VS then “crosses over” to use the VS on the opposite side of the plate.


My gut tells me this is wrong and is reflected by both OALL: Over-All lengths being way out of spec.

This CO: Cross Over dimension is kicking my butt.


Here is the response of my Fasti Rep after consultation with Germany:

“The difference you are seeing is due to the calculation of the control using

DIN 6935, and your drawing creation not.”


After spending several remote sessions with my VARs resident sheet metal guru, we finally got SW set up to create sheet metal parts using the DIN 6935 standard.


The tolerance dropped from 0.117 to 0.069.

Still out of spec too much to fold?


At the end of the day, the simple reality is this:

My guys have to reference a paper drawing to manually draw, add dimensions, and angles in the Fasti GPI.

I’m dealing with machine USERS here, NOT sheet metal gurus.

If it’s not on the print, they won’t have a clue.


Our whole process is driven by that paper drawing.


Does anyone know the PROPER way to dimension this scenario for Folding Machines, so that it will directly translate to the Fasti GPI?

OR,…is there some sort of manual compensation we need to include in the part program?

DIN6935 is all well and good, but it doesn’t practically address how my guys work.

It’s simply one of the many different bending methodologies built into SW.

I am deeply invested in the K-Factor method and it’s working for me.

Even if I started using DIN6935, I would STILL have the same problem, an incorrectly dimensioned drawing.


If I remove the bend, with CO dimension, it falls in spec and I would have no problem folding it.

My only option therefore, is to conclude that the CO dimension method is wrong.


Thoughts anyone?