Denford Software & Machines

I require to get "Perfect Fit" of mating parts with Lasercam and Techsoft

To get a "Perfect Fit" of components
1. Lasercam
Select the "CREATE OFFSET PATH" button and type in 0.07mm (Approxiamate RADIUS of the Laser Beam)

2.Techsoft
Select the "CONTOUR PATH" and type in 0.07mm (Approxiamate RADIUS of the Laser Beam)

ie, A laser does have a cutting diameter, so if you cut out a circle of 50mm diameter, its actual size would be less:

49.86mm which is 50mm - (2 x 0.07mm)
{Edit - this is incorrect - should be 1x0.07 = 49.930}

Also bear in mind that a laser does not cut perfectly parallel sides, so getting "perfect fit" results will vary according to material thickness.

so if you cut out a circle of 50mm diameter, its actual size would be less:

May I clarify something please?

If I remove a circle of diameter 50mm from a sheet of acrylic, the diameter of the hole will be 50mm but the acrylic 'plug' will be 49.86mm?

If I require a plug to fit the hole 'perfect fit', do I cut a hole that is diameter 50.14mm, leaving me with a plug that is 50mm diameter?

I realise that it is all internal and external dimensions.

Many thanks.

Keith

Having looked again at my previous post and it's incorrect, I should have put:
It's actual size will be 49.930 (1 x 0.07mm)

So if the laser is following the centre-line of a 50mm diameter hole, the "plug" would come out at 49.930mm and the hole would be 50.070

Denford Admin wrote:Having looked again at my previous post and it's incorrect, I should have put:
It's actual size will be 49.930 (1 x 0.07mm)

So if the laser is following the centre-line of a 50mm diameter hole, the "plug" would come out at 49.930mm and the hole would be 50.070

We have a VLS 3.5.

I have found the following offsets to work for me. I guess it is trial and error. I recently completed some test fitting on a range of pieces.

Cut a 20mm circle out of 6mm acrylic. Cut a 20.95mm plug from 6mm acrylic for a very tight fit. 20.90mm for a better fit that might reduce the possibility of a crack forming. I tested 20.35, 20.40, 20.45 and so on up to and including 21mm.

Contrast that with...

Cut a 20mm square (or 20x30mm rectangle) out of acrylic. Cut a 20.35mm square plug to fit the 20mm square cut out (20.35x30.35mm plug for the rectangular cut out).

Cutting a pentagon or hexagon out of acrylic and cutting the same piece with an external offset of 0.35mm for a snug fit.

A 20.35mm circle falls through a 20mm hole.

I have also experimented with several non-regular polygons and all are fine with a 0.35mm offset.

Keith,

Thanks for your testing and feed back on the forum, it's appreciated.