Practical matter: Increasing the spacing between objects in a drawing

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Practical matter: Increasing the spacing between objects in a drawing

georgesbasement
After more-or-less successfully having a couple of small (about 75 square inches, 0.25 inch thick) steel plates laser cut from my LibreCAD drawings this Fall, I am about to go to the next phase of my project.

Trouble is, my very cooperative vendor warns me that he'll need bigger margins on the drawings - the parts to be separated from each other are too close together. My latest drawings have about 100 parts, all to be disks destined to be made into small gears of 48 diametrical pitch, so I really need to heed his advice, or my little gears won't have good teeth.

It would be a herculean task to redraw & rearrange all those multi-sized disks, so my plan is to scale up my drawing by a factor of about 1.15, thereby enlarging everything by that factor, and then to select each individual disk and scale it back down to its original size with a scaling factor that is the reciprocal of 1.15.

Question: How do I make sure that each entity stays in the same relative position so that the margins between the entities are not upset ? My intention is that the distances between the centers of the entities be proportionally increased according to the original distances, which ought to increase the margins between the pieces in a consistent way.

An aside: As cut, the edges of the steel parts are so hard that they damage the steel files that I use to trim the remainders of the tabs by which they were attached to the original plate. I have learned that the convenient way to temper the hardened edges is to heat the parts with a hand-held propane torch to a temperature hot enough to coat the parts with blue-black iron oxide. Not bright blue - about 500 Fahrenheit (F)-  but blue-black -  about 1000 F. Then the filing and presumably the ensuing machining are uneventful. The tabs are necessary to keep from dropping the parts into the bowels of the laser-cutting machine.

Thanks
George
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Re: Practical matter: Increasing the spacing between objects in a drawing

LordOfBikes
Administrator
When you are scaling, you are asked for the reference point. This point will not move in the scale process.
So when you scale up, you may use an edge of the bounding rect.
When you scale down the single parts again, use their center as reference point.

I assume that your gears already have circles in their center. Then use the Snap Center function when you are asked for the reference point. This will snap to the center of the circle which should be the same as the center of the gear.
If there are parts without a center, you can add circles on a separate layer for reference point snapping. For production this layer can be deactivated.

I hope this works for you.

Armin
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Re: Practical matter: Increasing the spacing between objects in a drawing

georgesbasement
Yes - I used the bottom left hand corner of the plate as the reference point for the scale-up.

Then I started the scale-down process, one circle at a time, for which I had to be careful to
select the circle (by its center), then the tab (along with any transition lines used for smoothing
the arcs connecting the tab to the circle) hit <enter> and completed the scale-down with the
reciprocal of the scale-up factor, rounded up to increase the machining allowance a little.

After each circle was scaled down, I added a block-circle for the pilot hole for drilling the
center hole, which was necessary so I wouldn't lose track of which circles I had done already.

Thanks,
George
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Re: Practical matter: Increasing the spacing between objects in a drawing

georgesbasement
Some may notice that the resulting margins between entities won't be exactly uniform
because they're many different sizes. It turns out that large & small disks are mostly
side-by-side, so in the end I only had to adjust about ten percent of them. The drawing
is on its way to the laser-cutting enterprise and awaiting a cost quote.

Thanks,
George