Cutting Double sided parts?

[signtist]

I seem to get things off center from one side to the other!!!!
How do you get this centered? :confused:
John www.signgraphics1.com (http://www.signgraphics1.com)

[Brady Watson]

John,
The key is to pre-cut the stock so that it is exactly the right size, and plane or measure the thickness accurately. Then, center your part in the stock, and don't cut it out until the 2nd side - especially on parts that are non-symmetrical.

Plus...Put a block in X and one in Y to re-align your stock when you do the flip. You can also use a fine pencil mark.

-B

[michael_schwartz]

Let the machine/software do the hard work for you. When I need to accurately position material I use the machine to cut a fixture to hold it. This way you can just eyeball the x/y origin, and could be an inch off without any problems.

There is an explanation of the method I like to use within the following thread.
http://www.talkshopbot.com/forum/showthread.php?t=12338

[shoeshine]

I like shelf pins. I simply use a drill path to drill holes through the material into the spoil board at the corners out of of the cutting path (symmetrically of course so the piece can be flipped) then I put pins in the spoilboard. -bingo- easy registration.

Chris

[benchmench]

John,
What alignment/centering method are you currently using for double-sided machining?

[signtist]

Dan, Here's what I do.
On a 3'tall sign blank....4' wide.
I zero the bottom left, like normal.
Mark the left zero edge of blank on the table, then mark the right side (48")
Seems to me.....if I just flip it it should be right.

[larry_high]

This methed is use by Keith Outten in Va. of which I have tried and it works.
Scribe the center line of your table, then scribe the center line of the material. center your material on the table line= cut, flip material to same line= cut.
worked really well on full sheets.

[majohnson]

The way I've set my zero X, Y points so its repeatable, is find a point that is universal on your spoil board. Then using a 1/16" cutter, I will run the Y axis across cutting into spoil board. Then repeat the same process the length X axis. I then run 3 or 4 pairs of X, Y lines about 1" apart. So I have several reference point to use.

After that I take 2 blocks, one for each axis screwing them into the spoil board. Then run my X, Y axis to cut just the face of the blocks. So now I have 2 exact point to run my X, Y zero points

[magic]

John
I will be happy to come over and help you. I can make you some EZ jigs that align under different circumstances and show you the other methods suggested above.

Magic
7 1 4 84753-11

[lrheimpel]

John,

Take up Magic's offer to give you a hand. Nothing is going to be better than seeing someone do it and explain it to you on your machine.

I use the shelf pin method detailed above for parts that need to be dead on accurate. The spoilboard has drilled holes for my most common lenghts and widths already made.

For parts where being off by 1/16" or less doesn't make a difference, I just measure the width of the wood as accurately as I can (within 1/16 will do). If the piece will be turned along the Y axis I measure the X width. Or measure Y width if turned along the X axis.

My spoilboard has an "L" guide set on the XY origin, and I made a jig to set the origin on the same spot every time. So I machine one side by placing the work piece against the "L" with the bottom left corner at 0,0 for XY. Then turn the work piece along the desired axis and machine the other side.

[myxpykalix]

Hey MAGIC,

"I can make you some EZ jigs that align under different circumstances"

How bout showing all of us what you are talking about?

[magic]

First, It's important to know exactly where the center of the bit is after a C3.

I Actually moved the proximity sensors so the exact center is 0.0.

In the photos you can see that I also added small pieces of AL for a visual check, including a visual for the Z (upper limit).

In my case, all I have to do is precisely measure the work-piece and position it at 0.0.

For parts where the bit cuts over the edge of the piece, I made a bunch of spacers that are 3 inches - so the bottom left of the artwork starts at 3.3.

(You can also change the location of the artwork in your software but I usually forget, so it's easier to start at 3.3.

- - - -

In the case of anyone not moving their sensors:
Figure out exactly how far out the center of the bit is from 0.0. and move your artwork to start in that place.

You can also use that spacer, which looks like a square, to offset your work.

- - - - - -

For the really picked.... make your spacer so the finished offset includes your home position,

- - - -
And again I can't say how important it is to measure the work-piece accurately.

- - -

So all I have to do on a carving is create the artwork and F9 it in a box that's the same size at the material and 0.0. the material, on the bed of the machine.