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#1 2019-04-22 02:52:40

fcollingwood
Member
Registered: 2017-07-11
Posts: 22

2 stage lift

Hi Shahin

I, along with many other LCD printer users, have found that a high (8mm or greater) lift at moderate speed helps to improve the quality of the support side of the print (The other factor is a fairly long wait time before printing). However, we need to balance peel forces against lift speed.

What I would like to request is a two stage lift, where we can configure the height and speed of the first stage (the peel) independently of the second stage (Total lift height - first stage lift height). It would also be great if we can apply a calculation to the first stage - This way we could apply a speed calculation that is dependant on the area of the layer to help keep peel forces fairly constant for each layer.

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#2 2019-04-22 19:20:13

macdarren
Member
Registered: 2017-03-20
Posts: 243

Re: 2 stage lift

I already do this with NanoDLP on my LCD / Arduino based machine...by placing this in the G-Code after print box:

This does a very slow ZSpeed/10 lift for the first 2mm of the peel which generally get the print off the FEP
Then does a Full Speed pull for the remainder of the lift...just to get the print out of the resin so it can flow back.
You can add some other delays to assist curing and flow in other areas.

M107
G1 Z{[[LayerPosition]]+min(2, [[ZLiftDistance]])} F{[[ZSpeed]]/10}

[[WaitForDoneMessage]]
[[PositionChange  min(2, [[ZLiftDistance]])]]

G1 Z{[[LayerPosition]]+[[ZLiftDistance]]} F{[[ZSpeed]]}

[[WaitForDoneMessage]]
[[PositionChange [[ZLiftDistance]]]]

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#3 2019-04-22 19:42:16

Shahin
Administrator
Registered: 2016-02-17
Posts: 2,607

Re: 2 stage lift

Are you using RAMPS or Direct control?

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#4 2019-04-22 23:27:58

fcollingwood
Member
Registered: 2017-07-11
Posts: 22

Re: 2 stage lift

macdarren wrote:

I already do this with NanoDLP on my LCD / Arduino based machine...by placing this in the G-Code after print box:

This does a very slow ZSpeed/10 lift for the first 2mm of the peel which generally get the print off the FEP
Then does a Full Speed pull for the remainder of the lift...just to get the print out of the resin so it can flow back.
You can add some other delays to assist curing and flow in other areas.

M107
G1 Z{[[LayerPosition]]+min(2, [[ZLiftDistance]])} F{[[ZSpeed]]/10}

[[WaitForDoneMessage]]
[[PositionChange  min(2, [[ZLiftDistance]])]]

G1 Z{[[LayerPosition]]+[[ZLiftDistance]]} F{[[ZSpeed]]}

[[WaitForDoneMessage]]
[[PositionChange [[ZLiftDistance]]]]

GCode doesn't work with direct control

Last edited by fcollingwood (2019-04-22 23:30:20)

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#5 2019-04-22 23:29:58

fcollingwood
Member
Registered: 2017-07-11
Posts: 22

Re: 2 stage lift

Shahin wrote:

Are you using RAMPS or Direct control?

Direct Control

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#6 2019-04-25 05:06:25

Shahin
Administrator
Registered: 2016-02-17
Posts: 2,607

Re: 2 stage lift

If we add dynamic resin level, same effect could be achieved through using slow section speed. I am not sure how we could add it without making setup more confusing.

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#7 2019-04-26 12:31:43

fcollingwood
Member
Registered: 2017-07-11
Posts: 22

Re: 2 stage lift

Shahin wrote:

If we add dynamic resin level, same effect could be achieved through using slow section speed.

Not really. Slow section speed is fixed, I want to be able to make it dynamic depending on the layer surface area. It's the second stage of the lift that I want to make fast and fixed. Slow section height is also fixed. This is not really a solution, as I've noticed that the entire lifty in the slow section is slow. I want to have a 2 stage lift once it's put of the slow section.

People like macdarren already do this using GCode with RAMPS boards, so it is not something that just I find useful - The joys of direct control, I guess.

Shahin wrote:

I am not sure how we could add it without making setup more confusing.

Easy - Have a "2-Stage Lift" checkbox that only shows the 2 stage lift dialog boxes when it is checked

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