What's the CTB v4 file format?

This is an export file format for the compatible printers which use a ChituSystem motherboard.


Which printers are compatible with the CTB v4 file format?

New printers which require it: Elegoo Mars 3, Epax E10 5K, Peopoly Prime, Phrozen Mega 8K, Phrozen Mini 8K and more to be released.

Some older printers like the Elegoo Saturn with a recent firmware update needed to be compatible with Chitubox 1.9.

Note that they are still able to print files using CTB v3 even after the update if needed.

What’s new in the CTB v4 file format?

1. Two-Stage Motion Control or TMSC

The TMSC allows you to reduce the total print time while ensuring you a good success rate.

The lifting and lowering sequences of the model are now separated into two sub-stages, each of them has a height and a speed.

Lifting phase :    - first slower zone to allow the print to separate securely from the vat.

                            - then a faster zone to save print time.

Lowering phase:    - first a fast zone to lower and save print time.   

                                - then a second phase, much slower to let the object enter the resin with less disturbance and protect the weakest features of the print, thin layers, long supports...

How to setup in Lychee Slicer:

First you need to turn ON the TSMC option in the Global Parameters.

Then you will have to change the parameters in the Burn In Layers and the Normal layers section.

Lift Distance: From left to right the cells correspond to the Slower Zone lifting distance then the Faster Zone distance during the lifting.

Retract Distance: From left to right the cells correspond to the Faster Zone lowering distance (grayed out)  then the Slower Zone distance during the lowering

Note that one of the cell is always grey out. The parameter is automatically calculated based on the other cells values.

Lift Speed: From left two right the cells correspond to the Slower Zone lifting speed then the Faster Zone speed during the lifting.

Retract Speed: From left two right the cells correspond to the Faster Zone lowering speed (grayed out) then the Slower Zone speed during the lowering

A good starting point would be a total distance of 8mm for example:

We start with a 3mm lift at 60mm/s then 5mm at 150mm/s to save time.
Next, a lowering of 6mm at 150mm/s then 2mm at 50mmm/s to finish the cycle.

2. Light off Delay or Resting time.

You have to choose how you control the pause between each layer using the Light off Delay or the Resting time first.

How to setup in Lychee Slicer:

Using the Light off Delay:

This parameter allows you to specify a halt in the printing cycle, you can turn it ON in the Global Parameters.

Light off delay = Lift time + Halt time + Lowering time.

You can calculate it based on the speed in the parameters or simply measure a period of lifting + lowering cycle and add some halt time.

The larger the surface area of your print the longer the pause should be. 

Depending on the resin type, viscosity and room temperature 1s to 3s is enough to let the resin rest in the VAT.

Using the Resting time:

You can ask the printer to have a halt in the cycle between each layer, you can activate it in the Global Parameters by switching it off. 

Wait Before Print: A pause before the lift of the print.

Wait after print: A pause when the print is back into the vat after lowering.

Wait after lift: A pause after the lift of the print.

Simply change the time values needed in the parameters.

Just like with the Light off Delay, 1s to 3s is enough depending on your print setup.