Quote Originally Posted by rylangrayston View Post
Feign you did a great job of answering the question!
I love the skin on creamy soup analogy( im going to use that one! )

Ill add a few more things:
1. I Think a small positional offset that occurs when we turn the laser on and off is currently the biggest cause of prints having visible layers

......

1. Because we have designed our own current regulator circuit, we can turn the laser on and off much faster
I have some circuit questions:

Is your Vcc being loaded down from the laser transitions of on/off? Maybe it is pulling too much power at those instants which then lowers the available energy to your amplifiers?

To be clear, in some of your videos, the laser looks like it is moving very slowly, and other it looks to be extremely fast. Wouldn't the slow moving laser avoid the turn on/off problem except for one single point along the shape? Also wouldn't the code moving that on/off location create a spiral (like that spiral you spoke of in another thread)?



If this is all the case, then it sounds like you simply need better decoupling to your laser diode driver circuit. I dont know what kind of current it draws, but an LC lowpass filter should work to limit current spikes.

If it were me designing the circuit and I was facing that problem, I would first measure the spike droop to get an idea of how quickly the laser draws its current.

From there I would take that droop time and come up with whatever the lowest frequency component is. With your droop frequency now found, you can then figure out your filter values.

I would also see about the largest possible ceramic SMD capacitor I could fit in, and parallel that with a smaller 0.1uF.

After that, choose the inductor for your filter which is based on that droop frequency. They have lots of small SMD inductors, or alternatively you could use a resistor and just be less efficient.

For the rest of your problems you're on your own as I am only a hardware guy

hope that helps,




-UD