Draft problem in injection molding

Question

I have a design with two parts that would be produced via plastic injection (ABS injection molding). The two parts are small, around 10mm high each.

I have drafted both parts (inside and outside, 2°) but because of some buttons that can't be moved, the two pieces have a kind of "puzzle junction":

When the two parts are fitted together, the junction at the top of the "puzzle" is not well aligned because of the draft on different depths.

The delta around the buttons holes is very small: less than 0.15mm. I'm even not sure it would be noticeable especially as some buttons are going out.

how could I fix such problem?

Answer 1

put a jog in the parting line. Note that the human finger can easily sense a mismolded detail only 0.001" high and having a mismatch like yours will drive your customers nuts and probably piss off your bosses as well.

When HP was about to debut a new model of handheld calculator, they proudly handed a pre-release manufacturing prototype to Bill Hewlett to inspect. He immediately objected to the location of the parting line on the main housing which put a sharp edge on the assembly where the customer would feel it as the calculator nestled in their palm during use. This meant that the moldmakers had to cut a new mold that moved the parting line down away from the edges of the part at the last possible minute before product release, but Bill was right. I have owned one of these since 1976 and can vouch for its as-shipped quality.