Hello dear openFlexure community,
I’ve just finished assembling my microscope. However, I’m facing an issue where my objective lens is sticking out too far at the top, and I’m wondering what I might have done wrong. I purchased the full set from Sweden, so I didn’t 3D print anything myself everything came pre-assembled, including the objective.
Now I’m asking myself: do I perhaps need to adjust or calibrate something via the motor first? Because at the moment, it looks like the objective is protruding by about two millimeters. Has anyone encountered this before or knows what might be the cause? I couldn’t find anything about this in the forum at first glance.
Hi @SphaeroX it looks as though the z-actuator may be moved to its top position, lifting up the objective.
You can use the software to move the z-axis with the motor, but it is not always clear whether you need to add positive or negative z-steps. If you remove the z-motor then you can turn the large gear by hand. Clockwise turn should lower the objective (i think!). You will only want to bring the objective just below the stage, it will need to be almost touching the microscope slide to focus, with the specimen on the under side of the slide.
Then put the motor back on. Look at the assembly instructions, and only tighten the screws enough to hold the motor, it can be easy to strip the threads in the plastic.
One question. When this was shipped to you, was there any packing supporting the objective?
I don’t quite understand what you mean. The microscope came as a kit, not fully assembled. The objective lens was in its original packaging, so it was well protected.
I solved it through the software now, since I didn’t want to unscrew the motor again. The screws are the type that cut into the plastic. But I’m wondering how far I can actually move the Z-axis without eventually damaging the frame. I mean, the whole structure is basically made of PLA, and I’m not sure how far I can go with the travel range. This also applies to the X and Y axes.
@SphaeroX I misunderstood about the assembly from your first post.
The maximum travel is about 4mm total range for z and about 12mm total range for x and for y. The number of steps in the same for all axes, the mechanical ratios are different. There are 4000 steps per turn of the small gears, 8000 steps for the large gears. I don’t use the full range often, it is something like ±60000 steps. The stage will stop moving at the end of travel - the internal actuator column hits the top of the inside of the casing at one extreme and hits the foot at the other extreme. At the top the motors will just stop rotating as they are weak. At the bottom the main actuator screw will travel up, coming out of the large gear (or lifting the large gear in v7.0.0-beta4 and later). Neither of these should damage anything if you don’t carry on very far.
We are trying to build in more automatic detection of motion in the software to give users better information on range of motion and their current position.
