Troubleshooting
This section provides tips on how to save money and get the best quality out of your Metal Laser Cutting project, while also discusses common errors to look out for when setting up your file.
Common Errors
Minimum Cut Distance
Metal and plastics are prone to melting and warping under high heat and pose a significant fire risk. That means very thin and highly detailed sections may not come out as expected and are likely to be faulty or cause damage to equipment. It is recommended that the minimum cut distance is no less than the material thickness. For example 3mm Mild steel will have a minimum cut distance of 3mm.
This rule should be applied to all material types.
Surface Geometry
The laser cutter can't cut any surface or mesh type geometry. Please double check your file and convert surfaces into curve geometry.
Open Curves
Where possible, ensure all you shapes are closed curves. If you are cutting primary internal holes out of a larger shape, it is essential that these internal shapes are closed curves. Depending on your material we will need to add lead-ins to cuts, and closed curves will aid this process. You can check if curves are closed by selecting your geometry and clicking the properties tab in rhino.
Incorrect layers and order of cuts
If you do not separate your cut lines into primary and secondary layers your job may move before cutting is completed, resulting in inaccurate parts.
Corners melting
Often when cutting designs with sharp corners in sheet metal, the laser heats the material up in one place too quickly that it causes the corner to melt away. To avoid this we suggest filleting corners and avoiding sharp geometries.
Tips
How to Reduce the Cost of your Laser Cut Job
The cost of a job at the Fab Lab comes down to two factors: The type and quantity of material used additional to the amount of time it takes to cut your job.
ML Job Cost = Material costs + cutting time ($2.00 per minute)
Material cost
When processing larger sheet material, the Fab Lab does not require you to purchase the entire sheet. You will only be charged for the percentage of the sheet that you use.
If you want to save money on you laser job, nesting your geometry efficiently on the sheet will be best practice in keeping your material costs down.
Please note a bounding box plus a small wastage is placed around your geometry when calculating the material cost of your job.
You can estimate your material cost by multiplying your sheet area percentage with the cost of a FULL sheet on our Material Price List.
Time cost
Metal Laser Cutting time costs $2 per minute.
Etching and raster engraving tend to become expensive quite quickly. Reducing the amount of engraving will help keep unnecessary time-costs down.
Not only will nesting your job efficiently save you in material cost, but it will also save you time. The closer together you nest your geometry, the shorter the distance the laser head will have to travel between cuts, reducing your job processing time.
Setup fee
If your file is not set up correctly, we may charge you for the time it takes us to fix your work. Alternatively, we may reject your job. Please take the time to set up your job properly. It will save you time and money!
Tricks
Lead-ins
Lead-ins generate pierce points away from your geometry, leaving you with a cleaner finished edge. If you are interested in understanding how to do this, feel free to come in and have a chat with one of our Metal Laser Technicians. If lead-ins are necessary for your job our technicians will usually generate these for you. However if you would like to have more control over your job and cut quality it is possible to generate your own lead-ins.
The diagram below shows two variations of the same part; the first one does not have lead-ins while the second one has lead-ins generated.
Entry Points without Lead-ins: The laser will pierce through your material where the point is, which is on the desired cut. This will usually leave you with an undesirable edge finish.
Entry points with lead-ins: The pierce points are far away from the desired edges, leaving you with a clean cut finish.
To generate your own lead-ins you will need to download the LEAD-IN GENERATOR.GH
Tabs/ Bridges
If you need to cut small geometry that would generally fall beneath the laser bed, we suggest you add small tabs or bridges to your cut lines so that the pieces are held in place. Bridges are only recommended for thinner metals, and should be 0.1mm; small enough to push the piece out by hand later on.
If you’re going to use tabs, you should also draw a perimeter cut line around your parts so they can be removed from the larger sheet.
Filleted and Internal Corners
Another tip to avoid sharp and potentially dangerous metal edges is to fillet all corners in your design. It is also recommended that you remove material at internal corners if you wish to fold the material back in on itself.
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