Efficient and Smart Laser Cutting Path Export for Complex Assemblies

[Amyoqzy]

The current CAM tools in Fusion 360 for laser cutting only make sense for industry production processes. Where one single part is produced at a time. For complex objects, there are two main differences to this approach:

1. The paths are usually imported from a DXF or PDF into the control software of the laser cutter.
2. As many paths as possible are arranged on the stock material to save material and time.
3. Outlines of faces in many different orientation of the model are cut on the same stock material.

To illustrate the points above, have a look at this example. It is the wooden part which is laser cut from the same material:

To produce this case, 35 different parts need to be cut from sheets of wood. Producing part by part is obviously not very efficient.

Common Issues with Assemblies Laser Cut Objects from Sheet Material

• The stock material can be expensive. Filling the sheet as dense as possible with the cut objects is the ideal task for a computer.
• The thickness of the stock material varies. E.g. one batch of acrylic glass is 6.5mm, another 6.7mm. Laser cut objects are assembled using notches, therefore a small change of the material thickness will change many elements of the cut surfaces. Creating new cutting paths for a new batch, after changing a model parameter,  should be as simple as possible.
• Ideally, all parts of an object are cut from one sheet in one run. It is usually no mass production.

Feature Request - Laser Cutting CAM Module with the Following Features:

• I can select all faces to be cut in one single process, the orientation of this faces should not matter.
• I can specify the dimensions of the stock material (sheet size) and required padding (for fastener).
• All cutting outlines (with optional adjustments) are exported and arranged on the stock material.
  • The paths can be arranged manually on the stock material.
  • An algorithm arranges the paths optimally on the stock material to minimise the material loss.
• The arranged paths can be exported into DXF or PDF files, one file per stock material.
• The process should also be able to handle the production of multiple objects and optimise the paths in this regard. E.g. if I want to produce 5 copies of an object. Multiple similar paths can be arranged in a smarter layout on a single sheet of stock material.
• The process can be stored and updates the paths after parameter changes (e.g. change of material size) in the model with the minimum number of required changes in the arrangement.

The Problems with the Current Fusion 360 CAM Approach for Laser Cutting

• In the setup, I have to choose the tool orientation. To cut the faces of an assembled model, I would first have to "flatten" the whole assembly (take it apart), or use one new setup for each angle used.
• There is no simple way to arrange multiple cutting paths on a material sheet in an efficient way.
• There is no algorithm to arrange the faces on stock material in an efficient way.

My Current Work Flow

To use Fusion 360 to laser cut complex objects, I have to do a lot of manual work. This is especially frustrating if I have to change a parameter in the model.

• In Fusion 360
  • I create a copy of the model to protect the original from the following additions.
  • For each component/path to cut, I create a new sketch.
  • I place the sketch in the plane of the face of the component to cut.
  • In the sketch, I use the projection feature to create a final path from the component shape.
  • After creating sketches for all paths, I export this sketches as DXF files.
• In Adobe Illustrator:
  • I import the paths from the DXF files and clean up duplicated lines.
  • I manually adjust the path offset for the laser cutter and material.
  • I manually arrange the paths in rectangles of the size of stock material trying to cut the parts with minimal material loss.
  • I export the arranged paths into new DXF files.
• In the laser cutter control software:
  • I import the DXF file.
  • Adjusting the cut parameter.
  • Optimize the cutting path.

A good CAM module for laser cutting would make most of this steps obsolete. So I could just export a number of DXF files with the final cutting paths. After changing a model parameter, I could just export the paths again with almost no time loss.

[Amyoqzy]

To illustrate this idea, here all cut paths for the example project above, arranged on the stock material.

All this paths were collected individually and arranged manually on the stock material sheets. I am sure an algorithm could place the paths in a much better way and probably save one sheet of material.

[Amyoqzy]

In hindsight, I forgot to request another feature:

• A kerf correction can be applied to the design.

It would be nice if Fusion 360 automatically adjusts the generated cutting lines to compensate for the kerf of the laser as it already does with the CAM tools.

[pearlbluesoul]

I strongly echo this post, as layout is half the battle when dealing with multiple parts with complex features.  I work a lot in acrylic and its always a challenge making the most of a sheet, particularly when the cutter's software is the limiting factor.  

I would add: 

•  An optimizer that can analyze and if needed re-order the line segments as they are generated during sketching to allow the laser to cut a single path.  

Often if there are mirrors or patterns, the output that gets produced forces the laser to break up a profile into several smaller operations vs a continuous line.  This tends to cause issues where lines join when they are cut at different times and the material has changed temperature.  Likewise if I project a profile and then break the link, the resulting lack of constraints causes it again to break up items into separate segments, which could be resolved if the analyzer could observe these points and properly connect them.

•  Analyzer can observe and remove/highlight overlapping lines - results in duplicate cuts when in actuality it needs to just be one, which can often be hard to distinguish visually looking at the sketch.  

•  Likewise for construction lines, an option on DXF outputs to ignore them - The workarounds to extrude a model, project to yet another sketch, or eliminate these lines prior to export, are indeed workarounds at best.  There needs to be an option to remove them from the export process. 

•  Maybe an option to create a bounding cut line around the feature to cut away any excess materials - often when cutting out of a sheet, you end up with the siamese profiles sticking out that weren't cut away from the main piece of material, or thin pieces of material that can break away and leave sharp edges.  Helps allow better storage of the material and avoid the process of creating separate line segments just to cut the material off after the fact.  On a large cut, if the CAM software was calculating the best arrangement, it would be trivial to create a rectangular box around the final arrangement to lop off and 'deburr' the material being used.