Laser tool path display....( IDEA )

[Graham S]

Here is the way of getting very high angular resolution on the cheap as it were.

The leadscrew is attached to a semicircular "platform member" with two metal bands. These sit one on top of the other. When the lead nut moves it pulls the platform member by the metal bands. causing it to rotate on it's bearings. If the platform member is very near to being in contact with the nut (like photo not diagram) then the movement of the nut corresponds to a specific part of the platform members circumference.

So here is the proposed system: a nema 17 1.8degree stepper, 6mm diameter 1mm lead threaded rod. Over length Delrin nut or simple antibacklash nut. Standard ball bearings as thrust bearings. This gives a linear resolution of 0.0025mm in half step mode. If say the platform member had a diameter of 2" then the circumference is 2X25.4XPI = 159mm. The resolution of the linear part is 0.0025mm which is 1.56e10-5 of the circumference and so also of 360degrees. So the angle moved with a step of 0.0025mm is 0.005 degrees. That is a angular gearing factor of 160:1 between motor and platform member.

Quite good considering it is just a few bits of shim.

Obviously with gearing comes slower speeds but even at 160:1 the movement of the beam will be pretty quick. There is no backlash in the flex mechanism only in the lead scew so it is not perfect but still pretty cool I think.

Graham

Ref: Mechanisms and Mechanical Devices sourcebook.

[Graham S]

I did a little drawing of a unit for a Nema17 stepper and a 2" diameter wheel. With just 10mm travel on the nut I can get 60 degrees total beam deviation and with 0.005 degrees angle on the mirror (which equates to 0.01 deviation of the beam) I will get a resolution of 3mm.

At a range of 20M!! at least in the centre of the operating area

Graham

[arvidb]

Cool! I'm looking forward to see pictures if/when you get it done!

Arvid

[Graham S]

Hey guys, this is SO COOL:

http://www.synrad.com/Applications/video_clips.htm

Combine a laser scanner type system and a CO2 laser and have some fun! I intend to!!

Graham

[arvidb]

That is tremendously cool! I especially like the aluminium marking and the SS welding.

There are some interesting documents under the Documents menu.

Arvid

[DennisCNC]

Any one looked is this idea anymore?

It sure would be nice to have a laser guide for setting up pre cut parts.