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Z Axis limit switch design is backwards

Z Axis limit switch design is backwards

Updated on December 21, 2018 in Reviews & Experiences

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Andy 2 0 on December 14, 2018

So many BAD design decisions!! So many REALLY BAD marketing decisions… Here’s just one more!

My Slash OL has a limit switch at the TOP of the Z axis linear rail. (BTW this is the opposite of all the other machines we have tested) So the printer zeroes where it’s set by the user when the user calibrates with the Z axis zero setting with the app. As such the printer has the total height of the entire length of the linear rail hard coded. When the print starts the bed goes to that zero height… Then when it starts to raise and the vat refuses to release, because Uniz does not understand how a polymer needs to peel, the stepper on the Z axis lead screw misses steps and then eventually (hopefully) the peel happens and the bed raises. When it goes back down thanks to the missed steps and the lack of a limit switch at the correct location, the printer pushes the bed into the bottom of the vat and it again misses the same steps but in the opposite direction. If I did not use a raft and instead had a bunch of thin supports spread around… Making for much sharper spots… when the bed bottomed out the pressure could easily BREAK THE LCD!!! This printer is completely defective and a NONVIABLE product!!! It should NEVER have shipped!!!

<p>So many BAD design decisions!! So many REALLY BAD marketing decisions...  Here's just one more!</p>
<p>My Slash OL has a limit switch at the TOP of the Z axis linear rail. (BTW this is the opposite of all the other machines we have tested) So the printer zeroes where it's set by the user when the user calibrates with the Z axis zero setting with the app. As such the printer has the total height of the entire length of the linear rail hard coded. When the print starts the bed goes to that zero height... Then when it starts to raise and the vat refuses to release, because Uniz does not understand how a polymer needs to peel, the stepper on the Z axis lead screw misses steps and then eventually (hopefully) the peel happens and the bed raises. When it goes back down thanks to the missed steps and the lack of a limit switch at the correct location, the printer pushes the bed into the bottom of the vat and it again misses the same steps but in the opposite direction. If I did not use a raft and instead had a bunch of thin supports spread around... Making for much sharper spots... when the bed bottomed out the pressure could easily BREAK THE LCD!!! This printer is completely defective and a NONVIABLE product!!! It should NEVER have shipped!!!</p>

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Hanson 1 0 on December 20, 2018

Hi Andy, If there is sharp spots in resin tank, no matter there is miss step or not, it will cause LCD damage. It is not related to product design. Our engineer has many years experience in 3D printer design. We also did a lot of test for each new design. We had tested a lot of even very big solid objects to ensure they were peeled correctly. For some occasional miss step issue, we will fix it in our latest firmware. Please keep on upgrading our latest firmware to get the best performance.

Andy 0 on December 21, 2018

Please note that until the vat membrane was punctured by the spots on the plastic part above the LCD and the edges of the tape at the bottom we had already figured out how to get prints to complete with some semblance of reliability… We are NOT SLA newbies.

When the Bed presses down on to the LCD screen it puts pressure on the glass as it WILL do because thanks to UNIZ’s proprietary vat membrane which DOES NOT RELIABLY RELEASE, the Z axis misses steps. If you have a few layers already cured between the glass and the bed and the bed goes past what should be home and should have a limit switch to stop it… CRACK!

You say your “engineer” has “many years of experience”? First of all ONE Engineer! REALLY!? That explains a few things. It is obvious this “Engineer” does not look past their own nose when it comes to designing 3D Printers! UNIZ should do a little more HOMEWORK regarding examining this Engineer’s experience!

Third… You said… “Big solid objects”. We have found that ONLY relatively larger and more solid objects worked with the Slash OL!! Anything else we tried to print such as small jewelry examples or dental samples or even larger hollow objects the vat FAILED to release. Seems your Engineer looked at only ONE use case!

Fourth… Once the vat’s membrane was punctured we quit on ALL Uniz products! We probably will not be upgrading the firmware because at least our Slash OL is in the process right now of being taken completely apart… By MORE THEN ONE Engineer!!

Good riddens to BAD RUBBISH! SHAME on Uniz! We will be communicating to Kickstarter.com about the incompetence and immorality of the Uniz crowd funding campaign.

<p>Please note that until the vat membrane was punctured by the spots on the plastic part above the LCD and the edges of the tape at the bottom we had already figured out how to get prints to complete with some semblance of reliability... We are NOT SLA newbies.</p><br />
<p>When the Bed presses down on to the LCD screen it puts pressure on the glass as it WILL do because thanks to UNIZ's proprietary vat membrane which DOES NOT RELIABLY RELEASE, the Z axis misses steps. If you have a few layers already cured between the glass and the bed and the bed goes past what should be home and should have a limit switch to stop it... CRACK!</p><br />
<p>You say your "engineer" has "many years of experience"? First of all <span style="text-decoration: underline"><strong><em>ONE</em></strong></span> Engineer! REALLY!? That explains a few things. It is obvious this "Engineer" does not look past their own nose when it comes to designing 3D Printers! UNIZ should do a little more HOMEWORK regarding examining this Engineer's experience!</p><br />
<p>Third... You said... "Big solid objects". We have found that <strong>ONLY</strong> relatively larger and more solid objects worked with the Slash OL!! Anything else we tried to print such as small jewelry examples or dental samples or even larger hollow objects the vat FAILED to release. Seems your Engineer looked at only ONE use case!</p><br />
<p>Fourth... Once the vat's membrane was punctured we quit on ALL Uniz products! We probably will not be upgrading the firmware because at least our Slash OL is in the process right now of being taken completely apart... By MORE THEN ONE Engineer!!</p><br />
<p>Good riddens to BAD RUBBISH! SHAME on Uniz! We will be communicating to Kickstarter.com about the incompetence and immorality of the Uniz crowd funding campaign.</p>

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