How to turn off time saving control of the software

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whsjyboy
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Posts: 5

How to turn off time saving control of the software

Post#1 » Thu Oct 01, 2015 11:00 am

Hi,

I use version 1.8 software for printing. The new version software saves a mount of time because the software "knows" where the print is in the build area. Instead of doing a complete cycle (full movement in x direction), the vat goes half cycle or less. The phenomenon is also described by Robert Howle viewtopic.php?f=24&t=2786. Actually I quote a lot from his words.

Our problem is the tolerance for our parts is less than 10 um, the change of the vat moving pattern (from full movement to perhaps half movement) has impact on the printed parts. I attach two photos of the printed groove with 150um width. The groove is printed from the bottom to the top, so the photo shows different lays of groove. It can be observed that the "shift" of the layer appears on every 30 layers. When the printer begins to print the first 30 layers, the groove is straight. When printing another 30 layers, the groove totally shift 50um on one side. In the next 30 layers printing, the grooves becomes straight again. I have a feeling the phenomenon has something to do with the new feature of software saving time control.
200um_400um_change.jpg

200um_400um_middle.jpg


I was wondering if I can turn off the time saving control of the software for the price of more printing time, so that the vat can do full movement for each cycle.

Another solution might be using the previous software without the time saving feature. Does anyone could let us know where to obtain the old version software? Thank you for help in advance.

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Robert Howle
B9 Creator
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Posts: 6600

Re: How to turn off time saving control of the software

Post#2 » Thu Oct 01, 2015 3:58 pm

Send this message to Support@b9c.com Address Mike about the software question, he does write the code.

They can help with older version or answer about stopping the time saving feature. I assume u havn't turned "ON" the "Dynamic Vat Positioning" option (It is off by default). This can cause some shifting when used with smaller details due to variations in the PDMS thickness (refractive index issue). This happens because u are actually projecting the image through various area in the PDMS. This was a PDMS saving feature and not a time saving issue like the built in "short cycle" part of the software.

Robert Howle
Dance like nobody's watching!

whsjyboy
Newbie
Newbie
Posts: 5

Re: How to turn off time saving control of the software

Post#3 » Thu Oct 01, 2015 7:47 pm

Robert Howle wrote:Send this message to Support@b9c.com Address Mike about the software question, he does write the code.

They can help with older version or answer about stopping the time saving feature. I assume u havn't turned "ON" the "Dynamic Vat Positioning" option (It is off by default). This can cause some shifting when used with smaller details due to variations in the PDMS thickness (refractive index issue). This happens because u are actually projecting the image through various area in the PDMS. This was a PDMS saving feature and not a time saving issue like the built in "short cycle" part of the software.

Robert Howle


Thank you for help, Robert. I didn't turn on the "Dynamic Vat Positioning" as you suggested. You answer is greatly helpful. Before seeing your answer in that thread, I suspected the cycle issue but am not positive. I also suspected the reason is the vat moves slight in Y direction (X direction is movement direction) in each cycle, because the red color wood part under the vat are not 100% fit the track. I mean there are some space that the wood (if it is) have space to move on Y direction which can be observed if seen closely during printing process. I'm not sure if the space is designed on purpose or not.

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Robert Howle
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Posts: 6600

Re: How to turn off time saving control of the software

Post#4 » Thu Oct 01, 2015 10:08 pm

The vat movement (y axis) between the rails is not relevant, but is needed for the vat slide to move freely between the rails. The only thing that might affect "shift" is the position of the projector and the position of the build table. As long as the realationship between the build table and projector remains the same the vat movement in the y direction means nothing. The vat only serves to be the resevoir for the resin and to hold the PDMS which is needed for release. Binding in the z axis can cause "banding" in layers (i think due to layer compression). Are u using standard PDMS (Sylgard material) or something else?

Since the vat returns to full open for each exposure u should always be projecting through the same thickness of PDMS for each slice, therefore always projectiong through PDMS with the same refractive index. The short cycle is only about minimal movement to cause release over the dam. Like i think i mentioned the full cycle should occur every 16 layers/slices.

Can u post a screen capture of your layout (with supports if used)?

Robert Howle
Dance like nobody's watching!

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