Author Topic: types of galvo supported by lasershark board for SLA uv printer  (Read 1054 times)

jaswork7

  • Newbie
  • *
  • Posts: 3
  • Karma: +0/-0
    • View Profile
types of galvo supported by lasershark board for SLA uv printer
« on: February 05, 2018, 01:29:09 AM »
hi jeffrey nelson

my name is Jaspreet i am interested in one of your product "lasershark board". i am working on one of my client project which is "stereolithography uv printer" i know little about galvo motor through which we can achieve speed for SLA uv printer i been searching online and reading blogs and lot of people prefer your board to control galvo motors because its open source n custom.

 For starting to understand galvos i purchased cheap Chinese galvo motors which comes with laser projector (10k to 20k speed & 8bit or 12bit DAC) please check attached pics and files and i have few questions regarding lasershark board :

Questions:

1.is it possible lasershark board can control these Chinese galvo motor and galvo drive ?

2.do i need separate lasershark board for X&Y motor or one board can handle both X&Y
   motors?

3. is this board is just plug n play wires according to settings of hardware and software or i
   need to do some kind of programming to setup for galvo motors only not for stepper
   motors ?

4.do you have any windows application to run your lasershark board ?

5.according to your website new version of lasershark board 2.1a is available in your store,
   do u have its latest firmware 2.1a opensource also ? in case of any custom programming
   needed in future ?

6.can you tell me what else galvo motor  brands can lasershark board support accept
   Chinese laser galvos for example brands like (cambridgetechnology,SCANLAB,Thorlabs )?
   please suggest less expensive galvo motor n drive.

7. do u have any firmware which follow XY2-100 protocol ?

this is the link for chinese laser projector i bought from ebay incase link required :

(https://www.ebay.com/itm/20KPPS-30KPPS-laser-scanning-galvo-scanner-ILDA-Closed-Loop-max-30kpps-for-laser-/261517002270?rsta=en_IN(en_IN)&cnac=IN&mail=sys&e=op&unp_tpcid=xpt-auction-GXOTx&ppid=PPX000605&calf=9b28eff345c08&calc=9b28eff345c08&pgrp=main:email&unptid=7030a684-a82f-11e7-8875-5cb90192cb40&mchn=em&t=&s=ci&page=main:email&cal=9b28eff345c08&cust=1WL62553GY683905F)

sorry for the big link this is what they have

Thank you

Jaspreet

Macpod

  • Administrator
  • Full Member
  • *****
  • Posts: 167
  • Karma: +3/-0
    • View Profile
Re: types of galvo supported by lasershark board for SLA uv printer
« Reply #1 on: February 05, 2018, 11:07:49 PM »
Hi

1. Yes, the LaserShark sends signals that can be interpreted by the "galvo drive" (usually referred to as a galvo amplifier) in order to steer the galvanometers.

Galvo amplifiers are analog devices and should not be advertised with a bit rating (i.e. 8bit or 12bit). These values are associated with the galvo controller board that is sometimes shipped as part of the galvo/galvo amplifier kit... and intended for setting up very cheap laser lightshows. You do not need this controller as the LaserShark replaces this component (and is thus a means for you to save money)

The galvo ratings you should pay attention to are scan angle, the KPPS rating (kilo-points per second, higher is better), drift (less is better), settle time (shorter is better), linearity, etc. When purchasing galvo/galvo amplifiers it is best to purchase those that have differential differential inputs (3 pins usually, sometimes 4) to minimize noise.

The galvo you have shown appears to have differential inputs which is good. I am concerned that the galvos you have purchased are slow/upsold for what they are due to the presence of square mirrors. To support high speeds, it is best to reduce the amount of material that must rotated. For this reason higher speed and quality galvo sets usually have specially cut mirrors.

2. A single LaserShark is capable of controlling two galvo/galvo amplifiers (For X&Y control)

3. The LaserShark does not work with stepper motors. You do not need to program the galvo amplifier boards but you may need to tune the pid loop using the various pots on the galvo amplifier boards. I would not touch these until you need to.
Please see: http://macpod.net/electronics/lasershark/lasershark_usage_electrical.php

4. Some windows software is available. Prior to purchasing please review the following link and my github pages to verify it is what you expect: http://macpod.net/electronics/lasershark/lasershark_usage_windows.php

5. The source code on github for the firmware is the most up to date and is what is programmed on the boards.

6. The LaserShark will drive any galvo provided the input specifications of the galvo amplifiers match what the LaserShark will drive. This is mostly the same for galvo/galvo amplifier kits intended for laser lightshows (to accomidate the ILDA spec). LaserShark specifications are provided here:
http://macpod.net/electronics/lasershark/lasershark.php
and here:
http://macpod.net/electronics/lasershark/lasershark_usage_electrical.php

7. The XY2-100 protocol is a digital protocol. You shouldn't need a LaserShark to drive heads that use this protocol however some do seem to support analog input and these may be drivable by the LaserShark. I have found these heads are generally more expensive than just a standard galvo amplifier/galvo kit but would be happy to be proven wrong :)

« Last Edit: February 05, 2018, 11:12:13 PM by Macpod »

jaswork7

  • Newbie
  • *
  • Posts: 3
  • Karma: +0/-0
    • View Profile
Re: types of galvo supported by lasershark board for SLA uv printer
« Reply #2 on: February 09, 2018, 01:56:33 AM »
hi jeffrey nelson

Thank you for your reply and you cleared my previous points related to lasershark board there are few more things i want to ask about the firmware and hardware of lasershark board and galvo amplifiers:-

1. i am making my own custom host application for my client for SLA uv printer by using
    uart interface(i know its slow soon ll update to better interface) for now and my question
    is if i send X&Y axis values to lasershark board will that make galvo motors move
    according to values ?

2. i am asking this question for my knowledge only the galvo i bought from ebay they dnt
    provide much information regarding there galvo amplifiers they dnt provide any manual
    for there amplifier so for beginners its very difficult to understand the concept of galvo
    amplifiers the only  information i know is galvo amplifiers take +5-5 to +10-10 analog
    input and its factory setting 15   but what type of  signals(sine wave,triangle
    wave,square wave..?) they take and how much degree or galvo shaft will move according
    the signal we will give to galvo amplifier how can we calculate this according the pulse ?

3. can i use lasershark board for sla uv printer ?         

Macpod

  • Administrator
  • Full Member
  • *****
  • Posts: 167
  • Karma: +3/-0
    • View Profile
Re: types of galvo supported by lasershark board for SLA uv printer
« Reply #3 on: February 10, 2018, 01:59:08 PM »
Hi

1. Starting with the ascii interface (lasershark_stdin) is perfectly fine for prototyping, it was intended to allow an easy start for prototyping.
If you send X and Y values, yes, it will make the galvo motors move to those positions. You can read more about the lines that you must send by reviewing the lasershark_hostapp code.

Specifically:
lasershark_stdin_circlemaker
lasershark_stdin_displayimage

And perhaps most useful for learning the protocol:
lasershark_stdin_input_example.txt
This file will tell you the format of commands to send (i.e. how to set rates, move galvos, and turn lasers on/off)

2. The galvo amplifiers require differential analog signals. The differential input voltage provided is what designates what position the galvos move to. A differential value of -10v will make the galvo rotate to it's fullest extent in one direction and a differential value of 10v will make the galvo rotate to it's fullest extent in the other direction. A differential value of 0v will make it move to a centered position.
The amount of rotation will depend on how much you change the voltage from one point to another. In the case of the LaserShark there are 4096 "steps" divided in the case of your galvos by 30 degrees. This means each "step" under ideal circumstances will correspond with a 0.00732421875 degree change. Note that in reality you will never achieve this small/consistent an angle change due to various imperfections related to each component in any galvo system.

3. It will require you to develop software but yes? Others have already done this to varying degrees. Unfortunately their works are closed source :(

jaswork7

  • Newbie
  • *
  • Posts: 3
  • Karma: +0/-0
    • View Profile
Re: types of galvo supported by lasershark board for SLA uv printer
« Reply #4 on: February 16, 2018, 12:05:24 AM »
Thank you so much for your reply :):) if i have any doubt will ask you on this forum :)