Laser Cutting Pumpkin Jack o' Lanterns

[JDMc]

There was a bit of discussion on Slack about laser cutting pumpkins. Pumpkin is not currently on the Approved Material List, but there is possibility it could be added. Let’s use this thread to help the LCC decide if it should be.

The typical process for getting a material approved is to find a (Material) Safety Data Sheet and look at what is released when a material is combusted. Unfortunately, a SDS is unlikely to exist for pumpkin.

1. Does it create poisonous, corrosive, or otherwise unsafe fumes / gasses?
2. Is it a fire risk?
3. Will it damage the machine or clog the filters?
4. Does it produce unpleasant odours?
5. Does it etch well?
6. Does it cut well?

(Has it been cut/etched by other spaces / services?)

Links / Resources

Engraving on Pumpkins

• mounted entire cleaned pumpkin in bed
• recommends using a 4 inch lens for larger focus distance
• recommends against trying to cut through due to shell thickness and water content; recommends engraving
• recommends manually focusing between tallest and shortest areas being cut

Laser Cut Jack O Lantern

• mounted entire pumpkin in bed
• able to cut through with high power and low speed
• laser cutting pumpkin creates lots of ‘black goo’ when cut; cleans easily with wet cloth

http://www.designsponge.com/2013/10/the-ds-pumpkin-project-dan-funderburghs-magical-lasercut-jack-o-lantern.html

• cleaned pumpkin, cut out disk out of relatively flat face; removed skin
• ‘worked pretty well’
• smells ‘kind of pleasant and autumnal’
• had to put out small fires from time to time (though appears as this was on the cardboard they placed the pumpkin on)
• didn’t cut entirely through - had to finish by hand

Practical Considerations for Laser Cutting / Engraving a Pumpkin at VHS

• The fixed bed means that it will not be possible to etch or cut a full pumpkin - there isn’t enough space between the bed and the cutting head.
• The current / standard (~2.5 inch) lens is not ideal - it has a very narrow focus depth.
• The VHS laser doesn’t have a rotational stage, so cutting/engraving will be limited to one plane and will likely be skewed on a curved surface
• The VHS laser is not food-safe. Anything engraved/cut on the leaser is not for consumption and is for decoration only.

Alternative Approaches

• laser cut a stencil / template
• ?

Next Steps

1. Does anyone know a resource for determining combustion products of materials that don’t have a SDS?
2. Are there other example of laser-cut/etched pumpkins?
3. If pumpkin is conditionally approved for testing, is someone willing to champion doing some testing re: cut quality, odours, fire-risk and report the results back to Talk?

[jon]

I’ve done this in the past at another hackspace - our focal distance and bed configuration would make this very impractical - we don’t have clearance and depth to get anything but a sliver of pumpkin in the bed.

[Majicj]

As normally only dry things are being cut wondering if the moisture from the pumpkin “fumes” affect the filters?

[Janet]

That’s a good point - wonder if the moisture would combine with the carbon dust to form a coating on the filters?