PDA

View Full Version : Parallelogram for centering



Roger Lueck
09-14-2016, 12:52 PM
Has, or does, anyone use a parallelogram centering fixture to center objects for the X and Y axis on a laser engraving table?

Thank You,
Roger Lueck

David Somers
09-14-2016, 2:16 PM
Never done this Roger, but it should work fine if that approach works well for you.

I took the time to lock down my honeycomb table and adding guides on the edges (steel rulers, but any steel would work) that is in line with the X and Y axis.
My origin is set to the corner of those guides. So if I want something centered I draw the object up in Corel so that it is aligned with the edges of the page and then when I lay my raw material on the table I align it with the guides. My center is automatic at that point.

A simple alternative would be to use the multiple origin feature of your machine and set one up in the approximate center of your table. Save it. Then when you need to use it send the laser to that origin point and put your raw material under the laser and line it up with your LED Red pointer. Then run your job. You can tell most laser software to work with an origin point that is oriented at a variety of places around the drawing, usually back left, center left, center right, center left, center, center right, and front left, front center, and front right.

Pick a method that resonates well with your way of thinking and working. I bet folks out there have found some other good ways of doing this too?

Kev Williams
09-14-2016, 3:17 PM
Not sure I follow how everyone else 'centers'...

What I "center" is whatever text/graphics I'm engraving on the substrate.
What I don't center is any substrate in the machine. 99% of whatever material I'm engraving is placed in the upper-left corner against my stops. Depending on the job, sometimes I use the upper-right corner-

I have several spacers and stops for my machines, especially the Triumph because it's so big. Many are 12" tall that I use at the top of the machine as a stop, so the work isn't so far up! (35" is a long reach when doing small parts, getting them 12" closer helps!)

Many of my spacers & stops I cut from Romark or plex. I'll park a piece in the upper left corner of the machine, then let the machine cut it into an upside-down "L", say 1" from left and 1" from top. In Corel I'll put guidelines at 1" and 1", then place whatever I'm working on against those guidelines...

Since the machine itself cut the stops, everything engraved based on the stops will be dead straight, square, and centered. :)

Mike Null
09-14-2016, 4:10 PM
I do pretty much the same as Kev but I use a 30-60-90 triangle against one of the rulers on other jobs just to be sure the material is square. On others I find the center of the material then use the red dot.

David Somers
09-14-2016, 7:33 PM
Keep in mind, that on my Chinese machine the knife edge table was set to a variable height, blade to blade. And the Honeycomb itself was not square and had no edge guides, and set loosely on top of the knife edge so it could wander around as you raised and lowered the table. Once I had all that corrected I finally had some way to line edges up which I think fits what I described above. I also try to minimize any wasted materials so I like having my substrate aligned on the money if possible. Then my engraving or cut sets on it right where I wanted it. Essentially my edge guides on the honeycomb are the same as my page definition in Corel. Does that make my explanation more sensible?

Roger Lueck
09-21-2016, 10:46 AM
Thank you for your thoughts and experience on the subject, it is appreciated.

Roger