Auto Pierce
This feature, introduced in WAM 1.3, allows users to create pilot holes in place of small holes in the design file. This enables the precise placement of holes that can be drilled out at a later time. This can be useful when it is faster to drill out the hole manually or more accurately in cases where precision is needed. To view the patch notes of WAM V1.3, click here!
Procedure:
All the small circles in your design file are converted to pierce points in the last step before G-code is generated. As such the scaling and the offsets you select while setting up your cut will affect the final path that is converted to G-code. Essentially this means that the Nozzle Path (green lines in WAM) of closed loops that are smaller than double the kerf - or 2.54mm / 0.100in will be converted to pierce points.
The following cheat sheet shows what size the holes must be in your design software in order to be interpreted as a pierce point. (This assumes the default nozzle width).
It is important to know that depending on the Cut Path selected, you will see different hole sizes translate into an auto-pierce. This is because the Cut Path selection moves the nozzle path to the appropriate offset. For example, the Outside Cut Path will cut on the outside edge of loops except for any loops inside another. If there is an internal loop, it will be cut on the inside. This is to keep the cut size dimensions 1 to 1. For more information, please review the “Closing Notes” below and the Cut Path background information found here.
Any circles found within the range below, will become auto-pierced. WAM will omit circles found smaller than the range. Circles found larger than the range will be cut to size.
Cutting Path Input Diameter Range
Outside: 1.1mm - 2.6mm / 0.043in - 0.102in
Centerline : 1.0mm - 1.6mm / 0.039in - 0.063in
Inside: 0.1mm - 0.6mm / 0.004in - 0.024in
Please Note:
In the “Outside” cut path selection, any closed loop smaller than the limits shown above will not auto-pierced. WAM will omit all closed loops < 0.045in.
Size 0.001in holes will not show up in white on WAM but will show up in the cut file. Check by visualizing the gcode - learn how to visualize a gcode file here.
Closing Notes:
The kerf of the waterjet is ~1.2mm, so thinking of how your design lines will be cut with WAZER can be thought of as drawing with a thick marker pen. Imagine you are drawing circles with a thick tip marker pen, as the circle get smaller and smaller, the pen stroke gets closer and closer, until the stroke on each side of circle touches. At that point the cut will effectively be a dot, any circles smaller than this diameter will also effectively be a dot.
Anytime your design holes will be result in the hole being a 'dot', WAM will treat this as an auto-pierce. When cutting a dot, it is not necessary to drive the gantry system, a pierce at that point will do the trick.
Considering the point made above, we can see that while using an "Outside" Cut Path the auto pierce function will be performed when a closed loop is between the stream diameter or doubled, which is from 1.2mm to 2.5mm. Anything < 1.143mm and WAM will omit the loop entirely. An error message will display “WARNING- Offset size will remove geometry. Consider reducing the offset size or increasing geometry feature size” in the event a loop cannot be auto-pierced.
As for the "Inside" cut path, it is a bit different. The minimum diameter was chosen because of material response and kerf. The material chipped away by the nozzle stream is always slightly larger than the nozzle stream diameter, because of this we set the minimum auto-pierce diameter using empirical data. Any holes smaller than 0.6mm (~1/2 the stream diameter) will not be cut reliably, so any holes smaller than 0.6mm while using “Inside” Cut Path will be auto-pierced.
Below is an example of cut paths along loops that do not have an internal loop within. The offset is placed according to the path description.
Below is an example of cut paths along loops that DO have an internal loop within. The offset is placed according to the path description along the outside loop, but all internal features will have the offset flipped in order to keep the design intentions.
Hopefully this information has clarified the function and reasoning of the auto-pierce feature. If you have any questions or concerns, please reach out to Customer Support!