The Flatcar’s Flat Again!

So I wrote a couple of weeks back about how the 3D print of QTTX 131344 was no longer flat, and was decidedly bowed.  I received a couple of very good suggestions on ways to fix the problem.  Some from Rick De Candido will lead to a re-design of the 3D print to make provision for inserting brass bar strengtheners to help keep the car flat, something I can try on a re-print in the future.

The second suggestion from Steve Hunter, a fellow 3D designer and someone who is experienced in dealing with Shapeways materials lead to what appears to be a successful quick fix.  Effectively, using my wife’s hair dryer while she wasn’t home, I tempered the car to allow it to be bent back into the shape I want, and when it cooled, it should in theory hold the new shape.  Its been a bit over 24 hours since I tempered the car, and so far so good.  The next test will be to re-install the weights to give the car tracking ability, and see if the car continues to hold it shape as it should, or if the weight in the centre is causing the sag regardless of the tempering, which would indicate the bigger problem is an overall weakness in the design despite the material properties of the 3D printed UV Cured resin Shapeways markets as FUD.

Tempering the flatcar print with a hair dryer.  The car is clamped at the centre to a nice flat piece of wood.

As Steve pointed out in his comment, with Shapeways FUD/FXD, you could also achieve this with lukewarm water, but with the car painted and decaled, I didn’t want to take this approach and risk removing decals, even with the car clear coated.

Before and after of the car, the noticeable arch in the car is now gone, hopefully for good.

This kind of outcome where the minds and knowledge of others can be sought out and applied to both help me and anyone else who stumbles upon my blog is what I’d hoped for when I started writing.  Two great suggestions have lead to a design change that will hopefully help others down the road, but also to a simple fix (hopefully) for the car already printed that i am working on.  It will also eventually help anyone else who wants this car when I do put it up for sale on Shapeways, as I’ll be able to give them good directions on how to finish their car and make sure it runs properly.