Project update 7 of 75
Thanks to Demon3D (https://www.3dhubs.com/bristol/hubs/demon3d-kingswood) of the Reprap community we can show you a time-lapse video of one of the laptop’s parts being 3D-printed. The video shows the back left base part, which, thanks to having internal arches that were modelled on those used in Gothic Cathedrals, is incredibly strong despite a wall thickness of only 1mm and an overall length of 160mm.
We have had people on the forums express some surprise that a 3D printed laptop would actually be strong enough. Whilst being understandably unwilling to fully destruct-test a hand-assembled design, there are some key design criteria which, over the course of 18 months of work, are worth noting. Firstly is that the entire laptop is only 1.1kg in weight, where a standard 15.6in laptop would be more than twice that. Bear in mind that most 10 to 12in laptops aren’t even 1.1kg in weight! The reason for the greatly reduced weight is: no fans, no heatsink, no heat pipe, no hard drive. There’s very little in the way of metal in the entire design: the heaviest part by far is the LCD at 400 grams. By keeping the laptop’s design to a simple low-power strategy, there’s no runaway mass compounding which is inherent in 100% of the world’s mass-produced 15.6in laptops.
Destruct-testing of individual parts however was actually attempted. The base back part proved to be so strong that the testing had to be stopped for safety reasons. Also, as anyone who is familiar with 3D printing with filament will know, parts are often much stronger in the horizontal direction than they are vertically, due to something called "layer adhesion". An accidental side-effect of dividing the laptop up into separate parts is that every single one of the Bamboo plywood panels is surrounded on all sides by parts that are strongest in the direction in which the plywood is compressed, under tension, and held into grooves from all four sides. Amazingly - luckily - after eight months of design work where it was hoped that this strategy would work - it was some relief to find that it did.
One area of concern is the hinge. Whilst PLA from faberdashery has proven to be strong enough to hold the 400 gram LCD on its own without cracking, various other materials are under investigation such as Nylon, PETG and Polycarb. There is one small hinge part that is critical. The rest of the laptop can definitely be printed from good-quality PLA. Even medium-quality PLA has found to be an unacceptable substitute. PLA - Poly Lactic Acid - however has a glass point of only 60 Centigrade, which seems rather low for a laptop until we remind ourselves that this is a low-power laptop where the PCBs are in contact with Bamboo Panels, the top of the Computer Card is in direct contact with the aluminium structure of the keyboard, and the whole laptop is only 15 watts. The one major area of concern for heat dissipation would be the Power PCB, which, if that turns out to be problematic, can have the front right Bamboo Panel replaced with a decent metal heatsink: the PCB is directly behind it and can be attached to the heatsink with thermal sticky pads, just as are used industry-wide.
Thanks, though, to the 3D-printed nature of this laptop, we as a community can experiment with materials and ideas to find the best solutions. I’m providing you with that opportunity to do something hugely ambitious that’s never been done before: be part of a project that, at its heart, makes you properly feel like you own your own mass-produced hardware. We can call this not just the "Right to Repair" but the "Right to Own".