Chop Knives Enhancements I\'m working on

1. I100-04-05 Chop Knives
User Interface Functionality
Overview
There have been various complaints and bugs reported in Chop Knives over the past 10
years. Nothing was done because the code was hard to follow and Peter who wrote it left
years ago. This project rewrites chop knives with input from Terry Schoeder and Visy to
make it more reliable and useable. Terry did not use the previous version of chop knives
because of poor results. It took his programmers about 20 to 25 minutes to program scrap
knives manually for an ArtiosCAD rotary die layout. We hope that in future diemakers
will use the automatic scrap knives and only need to make minor edits, reducing the
programming time for scrap knives from 25 minutes down to 5 minutes per die.
Updated Scrap Knives Dialog
The new dialog for Scrap Knives is as follows:
Type in the parameters and click OK. It recalculates and replaces the existing scrap
knives, but leaves the stripping rules unchanged.
Description of parameters:
Size: Nominal size of the chop pieces.
Defines the nominal width and height of the rectangles that the waste is chopped into.
Generally the waste is chopped into rectangles less than or equal to this nominal size,

2. with slight exceptions in some circumstances to allow for the corner offset and bend
length.
Thin pieces
Thin pieces of waste can be a little longer than the nominal width or height, and this is
defined by the Thin pieces Length and Width. Pieces whose width is less or equal to the
thin width are chopped into pieces length less or equal to the thin length.
Offset: If not 0, the vertical knives zigzag left and right.
Corner offset: Distance chop knives are offset from a corner
Bend Length and Minimum Bend Angle:
The chop knife bends to meet the design perpendicularly, if the angle is more than the
minimum bend angle.
Arc Sensitivity:
Arcs less or equal to this radius are considered to be blends. Chop knives generally do not
meet the design on these arcs; they are positioned Corner offset either side of the arc. But

3. chop knives can meet larger arcs. (No change from the old version, but useful to remind
people what it means)
Standard Length Rules
Visy uses a standard rule with a hook for the shorter chop knives crossing the sheet edge.
I added a table of upto 4 standard length rules. A standard length rule with an optional
hook is used to replace short chop knives crossing the sheet edge. Standard length rules
are convenient for diemakers, because they can quickly make hundreds of them all the
same. The standard length rule is <= the length of rule it replaces, so that it does not go
outside the stripping edge.
Undo
Undo of Scrap Knives tool is fixed.
Angle Parameter Removed
The angle parameters for the Scrap Knife tool have been removed. Terry and Visy don’t
use it and it was difficult to implement during the rewrite. My apologies and please let us
know if anyone was using it.

4. Stripping Edge and Hook Parameters
The Scrap Knives tool uses the same stripping edge and hook parameters as the stripping
rules tool. For an mfg file, the parameters can be found under Options > Stripping edge,
and Options > Hook parameters. In Defaults, the parameters are set in: Manufacturing
parameter sets > Stripping rules > Stripping edge and Hook options
The standard length rules have their own hook parameters in the Scrap Knives dialog, so
its possible to have hooks on the short standard rules and not on the longer rules.
Continuous Rules for Edge Slots
Scrap knives are offset from corners by the Corner offset. In some cases, you want to
make the corner one continuous rule. In this case, we recommend that you add stripping
rules at the corners before using the Scrap Knives tool.
Move Scrap Knife
The chop knives produced by the Scrap Knives dialog can be moved with the Move
scrap knives tool, except for zigzag scrap knives. Zigzag scrap knives can be moved
with the Move tool, provided their length doesn’t change.
There are some bug fixes to the Move Scrap knives tool that makes it more useable:
Move long scrap knife
When long scrap knives were moved, the scrap knives they crossed were deleted – fixed
Adjust Bridges

5. When a scrap knife is moved, the bridges on this scrap knife are re-centered between the
other chop knives that it crosses. The bridges on these other chop knives are also
recalculated (but this is not relevant if you’re going to make rule paths).
Flipping horizontal/vertical
You should turn on the parallel checkbox in the Move Scrap Knives tool most of the
time. This prevents the drag flipping between horizontal and vertical.
Example of using the Move Scrap
Knives tool:
• Click the Move Scrap Knives
tool
• Turn on the Parallel checkbox
• Select the rule shown
• Move to align with another rule
• Click on the point to align with
Interface Testing Requirements
In my development test, I tested Terry's files and some of Visy's files. It would be good to
re-test some more chop knife mfg files, though we may leave this testing to Terry and
Visy.