I would suggest charging a minimum of $100/hr when configuring your costs for parts made on Any of the standard Glowforge machines. This rate may cover the repair cost if you do it your self-repairs and cleaning costs. This would be over and above the energy costs to power and cool the environment of the machine, then add material costs to make your products, and I use a 20% scrap rate for my materials. 20% may cover you for the machine inconsistencies, focus errors, and material quality.