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Author Topic: HELP!! does anyone know about floating heads for engraving??  (Read 7086 times)

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HELP!! does anyone know about floating heads for engraving??
« on: October 15, 2006, 09:40:58 PM »
I want to make a floating head for my cnc router to give a constant depth. does anyone have any ideas on how to make one of these or how they work,. Cheers, M :)
Re: HELP!! does anyone know about floating heads for engraving??
« Reply #1 on: October 16, 2006, 03:32:54 PM »
Good one Mark.
It's something I've been thinking about for a while, to get over a problem of slight differences in material thickness giving different line widths when using Vbits.
I don't think there has been anything on this in this or the mach2/3 Yahoo forum
All I can say is: aren't all floating heads just heads - with the power transferred to it by bands, so there's no real weight to be made to float?  And don't they have a ptfe collar riding on the workpiece?

What are the benefits to you of a floating head?

Jim
Re: HELP!! does anyone know about floating heads for engraving??
« Reply #2 on: October 16, 2006, 06:09:41 PM »
Due to the construction of my machine (extruded aluminium frame) I have problems with thermal expansion and contraction of the bed so even if I surface skim my vacuum table it changes slightly. Even the smallest change can make a big difference to the engraving with high and low spots especially when you only want to go 0.1mm deep. I did think about a PTFE collar riding on the work to provide the constant depth but then I though the removed material would get in the way if not properly extracted?? I think they use springs.. A sketch from someone in the know would be great!! ;D Mark
Re: HELP!! does anyone know about floating heads for engraving??
« Reply #3 on: October 17, 2006, 05:11:18 AM »
Your're right the swarf would need to be extracted, and a sketch would help...
I experienced a similar thing to you - after a perfect skim, - even using a square spiral to take any z axis irregularities out, the job still cut poorly because of highs and lows. The problem was the vacuum was compressing the bed down slightly. Obviously when skimming it wasn't turned on...

Lets hope we get some clues soon..

Jim

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Re: HELP!! does anyone know about floating heads for engraving??
« Reply #4 on: October 17, 2006, 08:22:50 AM »
A friend of mine uses a router and a MDF sacrifice sheet. He has a great eye for detail. He has noticed that on long runs, he also gets a fair amount of deviation. He had a piece of phenolic on a previous router and that fixed his problem in the past. One thought I had was the vacuum is removing the moisture from the MDF causing it to contract. Did you know that MDF holds enough moisture to carry a charge for powder coating?
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: HELP!! does anyone know about floating heads for engraving??
« Reply #5 on: October 19, 2006, 02:24:55 PM »
Mark
You asked about floating heads and got info about beds....Mmmm How do you feel about that? :)
Seriously though, is there any MDF on your machine? It does make it tricky. Mine is 19mm Foamex- closed cell structure pcv.

I remember reading something somewhere like...and that bracket will take one of the readily available floating spindles,....now...where was that?

Jim