Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: engraversoflight on February 24, 2016, 01:25:33 PM

Title: tabs
Post by: engraversoflight on February 24, 2016, 01:25:33 PM
So I tried cutting out shapes by onion skinning and sanding through with a drum sander as per my old conversation here.

http://www.machsupport.com/forum/index.php/topic,31824.0.html

It was not nearly as neat and glamorous as I had hoped it would be.  So back to the drawing board on hold down.

Tabs-does anyone use a trim router to cut parts out of the sheet?  I will be machining 4x8 sheets of 3/8 plywood.

Here is a pic of what I'm making:
Title: Re: tabs
Post by: ger21 on February 24, 2016, 02:24:00 PM
I use a trim router with onion skinned parts.
Title: Re: tabs
Post by: engraversoflight on February 25, 2016, 06:09:20 AM
do you put the ball bearing on the top of the bit, closest to the motor? what size bit is best?
Title: Re: tabs
Post by: ger21 on February 25, 2016, 07:14:08 AM
Bearing on the bottom, cut with the sheet upside down.
Something like an Amana 47090.
Title: Re: tabs
Post by: mattnedgus on February 26, 2016, 01:41:29 PM
Interesting to hear you want to move back from onion-skinning - I'm just in the process of wanting to move towards it!  What problems did you encounter?

I currently use the same method as Gerry by the sounds of it, except I turn the sheet over after cutting and use a hacksaw blade to cut through the tabs first, and then put it on the bench to go round with the trim router.  The trim router cutter is a larger diameter than the downcut I use on the machine which is one of the reasons I do this.

The problem I'm finding at the moment is that because the (in-this-case) birch ply is on show, without decent sanding, you can see the difference in where the tabs were cut vs where the surface was cut.  I ideally wanted to cut through all the way so I could leave the fresh-cut surface on display.  That or find a better method of thumb-backed sanding!!
Title: Re: tabs
Post by: engraversoflight on February 29, 2016, 08:36:40 AM
I wanted to do one pass on the drum sander but had to do as many as 5 on some pcs.  I couldn't put multiple pcs through the drum sander because it would bog the motor down too much.  So I had to break each one out individually.  That resulted in hours of manual work and a lot of scratches and bleeding on my arms from breaking the pcs apart.  I definitely got an education.  I would just really like to develop a sweet hold down system for cutting these parts out without much work after the fact.  We are a production shop, and my job is primarily finding out ways to minimize or eliminate manual labor from the process.  In my line of work, volume is the name of the game.  We are stealing work away from the Chinese exporters; but in order to do this, you have to be able to automate and eliminate steps to the final product.  I'd like to be able to cut these out and send them directly to paint, but at this point, I can't figure out a way to get it done.
Title: Re: tabs
Post by: mattnedgus on March 09, 2016, 06:33:44 AM
If I have any joy when I eventually try it (I need to re-level my spoilboard and [maybe] rebuild my Z first) I'll let you know!

Title: Re: tabs
Post by: mattnedgus on March 09, 2016, 07:01:41 AM
Out of curiosity, what thickness of skin did you leave?