Since the new year I have been experimenting with aluminium powder and I can now conclude that this material cannot be processed by this system. Compared to conventional LPBF printers the blue laser diode should have almost 3x more efficiency than the infrared lasers that are used. Unfortionately there is also another factor at play since the aluminium has a very high thermal conductivity. I believe the problem lies in the absolute power of the laser spot, the blue laser has a relatively large spot size of 0.15*0.18mm. Compared with other systems that generally have a spot size of <0.1mm the watt/mm2 is about 3x lower. This causes the powder to only loosely bond and because of the large thermal conductivity of the build plate the powder does not fuse correctly to the build plate. I believe the system will have to go into the 100watt power range with the same spot size as now to be able to print aluminium.

I have started recieving all the components of the new printer and I have started the assembly process, not all components have arrived but it is almost ready to start the motion system testing.

A selective laser melting machine contains a couple of risk that need to be mitigated so the machine can be used safely.

The last month I have been focussing on determining and improving the product density and also the skin of the 3d printed products. This is done by printing a lot of density cubes. Since the last update I have printed in total 68 density cubes to try to improve the density. The density is dertermined by first measuring the weight of the density cube and after that determining the volume by floating the cube under water, this gives the displacement of the water in grams and 1gram=1cm3.

Today i assembled the first pistons of the production model. The right part is fully assembled and the left one is only semi assembled and is still missing the seals and the 3d printed connection part that I will be printing on monday.For the next few months these pistons will be running an endurance test with 2000 layers being done in about 15 minutes. This will do almost 2 years of movements in little over 7 days.

The latest result of the process development really improved the quality of the part. the part on the right is the latest one, the one on the left is the one before that.

I found out that at some point i had changed the printing strategy from infill/inner/outer to outer/inner/infill. I spotted this error last time and corrected it for the latest print. This really helped with the outside finish of the part. The front part in the pictures is the one printed with the outer/inner/infill strategy and the rear one with infill/inner/outer strategy.

While doing some process development I'm also starting slowly with some design and realisation of parts of the next generation.

The upgrade to the nema 23 motors is complete and the first test print has been completed asswell. in the pictures to the side you can see the difference between my original beer opener and the newly printed one. The new one was printed with 0.05mm wall layers and 0.1mm fill layers.The top 2 images show both openers after some media blasting and the last 2 images show the new opener without any post processing.