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Some time ago, I bought an Elegoo Mars 2 Pro, and I really liked the product. This is my first resin printer and I am very satisfied.

What has been bothering me a little is in relation to the slicer. When I slice an item, Chitubox shows 3 hour/20 g (consumption), but this does not converge, when I print the final result is about 40 % higher than expected, this in both cases (time and resin consumption). I understand that resin consumption can be a little more relative, but time should converge.

My settings are the defaults provided by Chitubox, changing only the resin settings I use: 8 initial layers in 50 s and 2.5 s for other layers.

Is there something I'm doing wrong? Should these values converge with reality?

0scar
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wbrrtt
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2 Answers2

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It seems easy to calculate but it is not.

  1. Due to acceleration and deceleration, the movement time hard to predict. If you take a look at Atmel source code for movement you would get clear idea.
  2. Usually these boards contains RAMPS compatible firmware running on a separate micro controller. Any value change on this side such as movement parameters are not synchronized.
  3. Framebuffer being used to display layer which is slow and add slight delays specially for high resolution printers.

At the end I did expect better prediction with simple math, specially considering only very few parameters adjustable on chitu. The most probably your printer timing details on chitu are not accurate.

Shahin
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It's quite easy to estimate "close enough".

Compared to FDM printers, movement is way more simple, and there are only 4 different types of movements during a normal print:

  1. Lowering the print platform at the beginning of print (we can't know the starting position, so time needed cannot be really estimated)
  2. Printing bottom layers with longer exposure times. Speeds can be set differently from normal layers.
  3. Printing normal layers. Just like bottom, move build platform up and back down (slightly higher than last time), and do exposure with constant time.
  4. After the print is complete, lift the print up.

My last print job was 2249 layers, of which 4 were bottom layers. As you can see, everything else pales in comparison of the time needed for "normal" layers. So we can pretty much ignore them.

But the estimate is wrong. Luckily it's very easy to fix closer to the reality. This page shows how to do it, search for "Layer Print Time Compensation"

Since print time is so predictable, it's only a single multiplier value. The easiest way to set this up is to slice a project, write down estimated time AND amount of layers. Then when the print is done record the time it actually took, open the compensation window (gear icon on the right side of Layer Print Time Compensation), and enter all the values there. It will calculate the multiplier for you. Also note that this setting is per-profile, it will be different for different exposure times, movement speeds and layer thickness.

Jupp3
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