Mold Material That Can Be Laser Cut

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1Bad88

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I designed a layered mold for my landing gear with a plan to laser cut the layers from 1/4" MDF. I have tried 2 different kinds of MDF but am unable to cut through it. Is there another material that is cheap and can be laser cut? I am considering cardboard with a coat of body filler as an alternative but I worry that it is too inconsistent in thickness and will be very fragile.
 

Vigilant1

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XPS foam reportedly cuts well with a laser, at least according to this guy:
XPS FOAM, Cutting a Movie Title

For his purposes, he says up to 10mm thick foam produced an acceptable kerf (multiple passes).

It is cheap enough to try. The pink (Owens Corning) or blue (was Dow, now Dupont) sheets are generally available in various thicknesses at home supply centers.

Use ventilation. The foams with higher compression ratings are a bit stiffer. 15 psi and 25 psi are widely available in many stores, stuff greater than 100 psi is available through special order, higher expense.
 
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Jay Kempf

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I have a 100/90 watt laser cutter and MDF is pretty dense and tough but it can be cut. XPS and extruded poly styrene cut easily but careful.

Hotwire and then bend into shape?
 

Vigilant1

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Also, if you want to use XPS and stay with your planned 1/4’ thickness, you could either:
1) Buy thicker 4'x8" sheets (e.g 1” thick) and use a hotwire to slice it to 1/4" thick sheets. Or
2) Buy the XPS fanfold insulation that is approx the right thickness. Looks like this: Home Depot Foamular Fanfold

The fanfold is 48" wide but has a crease/fold every 24”, so that might be a little inconvenient depending on the size of your mold.
 

1Bad88

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Also, if you want to use XPS and stay with your planned 1/4’ thickness, you could either:
1) Buy thicker 4'x8" sheets (e.g 1” thick) and use a hotwire to slice it to 1/4" thick sheets. Or
2) Buy the XPS fanfold insulation that is approx the right thickness. Looks like this: Home Depot Foamular Fanfold

The fanfold is 48" wide but has a crease/fold every 24”, so that might be a little inconvenient depending on the size of your mold.
Interesting option on the fanfold insulation. I wonder if I could snag a little piece before buying 200 sq. ft. of it.
 

Vigilant1

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Interesting option on the fanfold insulation. I wonder if I could snag a little piece before buying 200 sq. ft. of it.
It is pretty common at construction sites, you could go dumpster diving. A contractor who installs vinyl siding might have some you could have or buy, it could be worth some calls to local installers .
 

Geraldc

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I asked abut getting some 20mm ply lasercut but the fibre laser would not do it. CO2 would probably do it..
I had the ply waterjet cut with amazing results.
MDF can be waterjet cut as well
 

Geraldc

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A simple diy CNC cuts/shapes MDF beautifully.
Parts I wanted needed square internal corners so I got them waterjetted.
CNC Router (I have one )would leave round corners the radius of the cutting tool.
 

rotax618

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A CNC path can have a a finishing cut that can use a very small dia. tool if that is what is required, or a “dog bone“ corner which is good for stress relief and allows sharp corner fit.
 
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