In about 2 months ago I found a problem with all “round” printed parts. I.e. bolts, rivets, rods, etc. With any orientation diameter of such parts was smaller for 0.2 - 0.3 mm. For me it’s big difference, because I print really small parts. Difference 0.2 can kill print when you try to print bolts with diameter 0.5 mm.
So. After investigation made by dealer, Creative Tools Sweden, they found that problem is in grey resin. They tried to print my bolts with diameter 1.2 mm in 3D and got printed parts with diameter 1.0 mm. When they tried to print same parts in clear resin, they got bolts with diameter 1.5 mm! So problem in resin.
We print using high - temp. Imagine rounded coin - 7cm diameter , 4mm thickness. We have to print it vertically with supports only on sides.
Print lasts sth about 8-10h. Every time print is oval. It gets additional 1mm of lenght. I suppose beceause of gravity. So we add this 1 mm before printing to the width.
Every resin has its sins
It works when you print something like coins or bolts. But when you print for example scale axles, scale drum brakes which will be assembled later by customers, and other complicated parts, sometimes it’s not so easy to add those 0.3 mm. This is just one example of drive axle and this is not most complicated part in our models.
Tires, rims - everything with round shape should be corrected to this difference. And difference is floating. Sometimes it’s 0.2, sometimes it’s 0.3, for outer diameter of tires it was 0.4
