So what to do with a working D910HD.
The answer seems obvious when you know that I have a 1.1 printer that I use for some jobs, but not as often as I wished, because the print sizes and resolutions of 1.1 and 1.2 printers do not match - or if you read the summary on the contents page.
There are three hardware issues to be solved for using the D910 on the 1.1 printer.
First the focal point shift.
Second the mounting of the projector.
Third removing the glass from the projector lamp.
On the Titan forum there is a user Kentaro who did an stl for the gasket - many thanks -, which I downloaded. First I thought about cutting the gasket from rubber, but than remember the bottle of Spot-E I always postponed to try out. This is my chance to kill two flies with one stroke and I print the gasket using Spot-E.
I'm prepared to do some test prints to get the exposure right - new resin and all. But I'm denied that, it works out right from the start with the same parameters that I use for Spot-HT.
I added a lot of supports to keep the gasket in place, just to be on the save side.
Later I will find out that I can cut exposure times nearly to half without ill effects and that the additional supports are unnecessary.
Spot-E is really rubbery and elastic and feels nice. it does not loose elasticity ( and it shouldn't) under UV light as far as first tests show. It seems to cling to the build plate like Paris to Helena. It might be worth to try on large models that warp so much that they come off the build table - if the rubbery consistency doesn't pose no problem.
Before anybody asks, I do not know whether it is castable, but doubt it.
Installing the gasket was a breeze. Remove the top and front bezel. Remove the black lens ring and you can access the 3 screws holding the lens system. This is where you will put the gasket. You will have to replace those screws with M3x10 countersunk head screws.
If you find me obsessed with screws, keep in mind that I have opened and closed the projector at least 25 times.
To keep live simple, or better to start to make live simpler, I decide to keep the original projector mount and just add an adapter for the D910HD. I have an CNC milling machine, so I cut it from acrylic glass with high enough precision - which isn't really that hard, because the only thing that has to be precise is the size and location of the holes and you can manage that with a drill and a drill rig.
The adapter and the size of the projector will shift the projection more to the front, which isn't a problem.
The 1.1 has less room below the x-axis base plate, so you can not get the projector far enough for 70 um resolution, but 50 um is fine. Also 30 is easily possible, probably 25, I didn't check. As I use only 50 and 30um, I'm content, but if you need 70um you will have to look somewhere else.
The third point is not really worth a comment, except that you have to unfasten 5 and fasten 4 screws, screwssssss, screwssss....
The hardware done only the software is missing.
Printer parameters are selected by the means of a configuration file. So I add 2 configurations one for 30 and one for 50µm.
The first choice is which driver to use. There is a 1_1_0 and a 1_2_0. It has to be the latter one, because that supports the new projector. Other obvious values to change are print resolution dependent values (for the 30um) and projector resolution values.
That should basically be it, but it isn't the build table movement is not correct. The way will be clear as soon as you realize that the 1_2 version uses half steps, while the 1_1 uses full steps.
So you also have to change the z-resolution and you have to double all step values, which appear in parameter pages and some calibrations.
Because the projection is further to front you will have to change to change the y offset as well.
And that's it copy it to your application (I use a Mac so it has to be copied into the Application Package) and you are ready to go.
The picture shows the additional fan. It's not needed anymore, but where else would I store it ?