Searching for accurate Z-dimension prints


I am trying to get accurate dimensioning in the Z-directiion. The print that I am looking at takes all the platform in the XY plane, and is intended to be about 0.4in thick. I have had some issues with bad accuracy or jamming, and since I still have not found a “perfect print”, I wanted to share what I have done so far and what my results have been in order to see if anybody could help me.

First, I used ~standard settings for PR48’s 10 micron profile. I followed the advanced printer calibration mentioned by @scott_chabineau in this post (First layer exposure time of 0.01 s, burn-in layer exposure time of 6s, burn in wait time of 75s, burn in separation velocity of 1 rpm.Model separation slide velocity of 0.5 rpm, and model wait of 20s.) This were my results:

While I was able to finish the print without jamming (and I have learned to appreciate that), my print shows a poor profile in the section that was attached flat to the build head. As you can see in the picture, the section on the right is curvy, and the edges have a smaller thickness than the middle section. My thoughts after seeing this is that maybe I need more exposure and/or more LED current, since the part seems to be detaching on the edges due to the weight.

So I went ahead and changed the settings for a higher exposure settings.I increased the LED current from 150 to 250, the burn in exposure from 4 to 10 s, the burn in wait from 75 to 90 s, and the model exposure from 4 to 6 s. Unfortunately, the part jammed. I was not surprised to see jamming happening due to high exposure.

I did change my settings a couple more times (now reducing exposure/LED current from the values presented in the paragraph above) and still experienced jamming. For the minimum exposure settings ( model exposure of 3.5 seconds and model slide velocity of 0.5 rpm, and LED current of 170). I still experienced jamming. However, this jamming took longer to occur, and I was able to extract the following piece:

This part is by no means straight. In think the reason for this is also jamming of the build head pushing the print away from its calibration precision.

My issue now is that if I reduce exposure settings again it will seem like coming back to square one where I was obtaining my curved surface. I want to come up with a systematic way of printing flat surfaces with high z-accuracy while avoiding jamming. I have been using the same resin tray throughout but I do not think that this has to do with the issue

I would love some input on this from people that have had more successful experiences on this issue.


The reason that large parts curve where they attach to the build head is that the resin actually shrinks very slightly as it cures. For this reason, it’s often not possible to print parts that take up the entire build area. There are ways to reduce this effect, most notably by using a raft, but that requires that the part be small enough that the raft can fit in the build area.


I see. Maybe also reducing the part a few pixels and using OPC would help. However, I also experienced this in smaller, thicker parts that took a bit less than half the area. Is that also expected? My thought was to increase exposure settings for the first few layers.


Yeah, unfortunately it happens even with smaller parts. But a raft can work wonders!