# Stage range and location errors
**URL:** https://openflexure.discourse.group/t/stage-range-and-location-errors/2241
**Category:** Request Help
**Created:** [21 August 2025 01:07 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241 "2025-08-21T01:07:33Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@touchari](https://openflexure.discourse.group/u/touchari)
#### Post date: [21 August 2025 01:07 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241/1 "2025-08-21T01:07:33Z")
Hi，All
I recently calibrate the stage range with etalon，found the range is about 10mm in XY direction， is it reasonable？
I wonder the travel rang is sufficient for most users？
Second question，Since a stepper motor used，why not remove the gear and drive the thread directly to avoid the return difference？
Thanks
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### Author:  [@WilliamW](https://openflexure.discourse.group/u/WilliamW)
#### Post date: [21 August 2025 08:27 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241/2 "2025-08-21T08:27:48Z")
The stage range is nominally 12mm×12mm. This is a compromise between range, stability and overall size. The OpenFlexure Microscope is not a universal microscope, there are tasks where it excells but it is not possible to do everything.
The stepper motors on the microscope have internal gearing (about 64:1 ratio). There is backlash in that gear train, so removing the Microscope gears would not actually make much difference in that respect.
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### Author:  [@touchari](https://openflexure.discourse.group/u/touchari)
#### Post date: [8 October 2025 13:40 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241/3 "2025-10-08T13:40:46Z")
Hi, I’m planning to expand the XY travel range of the specimen stage to about 25 mm. However, after I changed the value of _sample\_z_, I noticed that the distance between the motor and the center of the stage changes proportionally.
Could you please tell me whether this proportional change is necessary?
If I want the motor’s XY position to remain unchanged, how should I modify the structure code?
Otherwise, the actuator’s travel range will scale up proportionally, which will cause it to be limited by the enclosure and prevent it from effectively reaching the 25 mm range.
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### Author:  [@touchari](https://openflexure.discourse.group/u/touchari)
#### Post date: [8 October 2025 13:41 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241/4 "2025-10-08T13:41:53Z")
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### Author:  [@WilliamW](https://openflexure.discourse.group/u/WilliamW)
#### Post date: [9 October 2025 07:39 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241/5 "2025-10-09T07:39:11Z")
Making the stage very tall is likely to make it much less stable because the legs remain the same thickness. It will be interesting to know how it behaves in reality. @chish is also working on this in merge request [!430](https://gitlab.com/openflexure/openflexure-microscope/-/merge_requests/430)
The stage motion is set by the height of the stage and the lever ratio for the actuators. The lever ratio determines the resolution of the motion of the stage.
To have a larger motion with the same resolution, the lever ratio to the actuator needs to remain the same so that one turn of the actuator is the same motion of the stage. That then also needs a longer actuator travel to match the longer stage travel.
If you want to keep the same actuator motion for a larger stage motion this is less resolution in the stage motion, but it will enable you to keep the actuator in the same place. You will need to modify the parameter `xy_lever_ratio` in the same proportion as the height of the legs. Note that the relevant height of the legs is less than the `sample_z` by the thickness of the stage, `stage_t`.
If you are modifying the height you will need to be working from a recent fork of the `master` branch. For merge request [!430](https://gitlab.com/openflexure/openflexure-microscope/-/merge_requests/430) we found that there were a number of unrelated dimensions of the stage that were tied to the parameter `sample_z`. I re-parameterised the stage in [!429](https://gitlab.com/openflexure/openflexure-microscope/-/merge_requests/429) and [!435](https://gitlab.com/openflexure/openflexure-microscope/-/merge_requests/435). You probably really want to use the most recent `master` as that will include the new nut traps for motor mounting. This was mainly implemented in [!448](https://gitlab.com/openflexure/openflexure-microscope/-/merge_requests/448), but there were a few more fixes after that to make the cable tidy covers fit the new lugs. Master after [!501](https://gitlab.com/openflexure/openflexure-microscope/-/merge_requests/510) last week now has all of the parts changes that are planned related to that important update from @ffesti.
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### Author:  [@touchari](https://openflexure.discourse.group/u/touchari)
#### Post date: [9 October 2025 09:02 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241/6 "2025-10-09T09:02:56Z")
thanks，i will try it，and using different material may be helpful
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### Author:  [@touchari](https://openflexure.discourse.group/u/touchari)
#### Post date: [11 October 2025 15:08 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241/7 "2025-10-11T15:08:58Z")
another question， diameter of stage is 40mm，and objective is about 20mm， which means the max range is about 20mm circle. If I want to make it exceed 25mm， what should I do？change the diameter of stage？
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### Author:  [@WilliamW](https://openflexure.discourse.group/u/WilliamW)
#### Post date: [11 October 2025 20:45 UTC](https://openflexure.discourse.group/t/stage-range-and-location-errors/2241/8 "2025-10-11T20:45:11Z")
Getting a very large range of motion is not trivial. Enlarging the central hole will cut back into the nut traps fairly quickly. The Upright version puts the objective above the stage, the illumination is narrower which would help a bit. There is also the position of the optics mounting screw, which gets odd if the stage is too tall.
It should be possible to move the legs out to a larger radius to give more space inside the stage.