Fireman Helmet Vacuum Form Mould

Create left and right mirror halves of a fireman's helment as a proof of concept to improve on an antiquated design.

Estimated Duration: 8 hours
Actual: 7.5 hours
Costing Accuracy: 94%
Work Breakdown:

  • 2.5 hrs CAD
  • 2 hrs setup & general labour
  • 3 hrs VMC machine time
  • Cutter consumption - negligible
  • Material: MDF

As Chris Wright describes it, current helmet gear used by the modern fireman is antiquated and imposes risk. His thesis was to prototype a new, modern, more functional and modular fireman's helmet design by creating two vaccuum mold halves, vacuum-forming plastic over the moulds, and joining the two together to create the actual prototype. Once again, this project was funded by a student budget so the costs were very, very low to the tune of $20 worth of MDF board, $8.00 worth of carpenter glue, and the rest CAD, machining, and Chris' own blood, sweat, and tears to put the finishing touches on the rough-machined mould halves. The mess was anticipated from experience with the previous MDF project and mitigated with ongoing cleanup using the shop-vac. Cutter wear was again negligible and thus only a fraction of the tooling cost included in the overall costs. Besides, I needed a couple of 6" carbide square and ball cutters anyway.

Starting out as a set of 12x12 boards glued up 10 at a time, the block was drilled and screwed from the bottom, mounted, and milled in two passes - a roughing pass using a 1/2" 4-flute 6" carbide endmill at 4000 RPM to remove the bulk of material using a waterline algorithm, followed by a two-part finishing pass with a 1/2", 4-flute, 6" ball mill at 4000 RPM using opposing lateral profiling passes. The length of these carbide cutters made a screeching noise throughout that could have been avoided using a different RPM setting, but the job was small.

As with the previous project, the cutter left fluffy edges only near the glue joints that were cleaned up in the second pass with the ball cutter. The second pass incremented in 0.05" steps with a 0.005 scallop height constraint. First pass took 1:05 minutes, with the second pass taking slightly under 25 minutes.

Chris made excellent work of the mould, forming his two halves and finishing the product exquisitely. I believe he got a very good mark for this project and was in discussions with some representatives from a helmet (and other equipment) manufacturing company with a bead on a potential job with the company. Nice work, Chris.

Click on each photo to enlarge.