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Scaling Image For Cut


#1

This may be a really stupid question because I am probably missing something extremely simple. Where do you scale the images to cut? Is it in makercam or is there somewhere in ground control? Is is it something that needs to be done before any of that?


#2

You should scale the drawing in your CAD program and then produce the gcode from the CAM program. It is possible to change the scale in makercam (selecting items, selecting scale, and entering the scale increase). But I recommend doing it in the CAD program. GC won’t do any scaling… it just reads the gcode and sends it to the arduino controller.

What’s your planned workflow (CAD program and CAM program)?


#3

I’m just going off of 2d images to cut so it should be scaled om the SVG image before I upload to make came right? It would convert whatever size the orginal picture was to the cut in Gcode. I’m really new to all of this but if I used Publisher to create the exact size made that a SVG then convert that should work for me without dealing with any 3D cad programs right?


#4

As long as the SVG is “scaled”, you’re going to be good. Just bring it into a CAM program (makercam for instance) and produce the gcode. If, when you load the gcode in GC, you see it too small (or large) on the screen, then you should go back to Publisher to correct the scale.

You shouldn’t need to use any 3D CAD program with the Maslow. You just need to get a scaled SVG and if you can do that in Publisher, you’re good to go. If not, then maybe use a 2D program like inkscape, freecad, visio, etc.


#5

Awesome thanks for your help


#6

One thing that I’ve done to help with scaling since not everything imports into MakerCAM with the correct dpi or the scale just seems off; is to put a square of a known size (6 in x 6 in or 10 cm x 10 cm) in my SVG file. That way in MakerCAM I can line it up with the grid and scale the entire drawing until that is correct. It also gives me a verified by way to calculate the ratio to scale by. Delete the square when I’m done.

Really wish makerCAM has a “measure” feature :slight_smile:


#7

I wish it did too.

Another thing to play with is in the MakerCAM preferences there is a default pixels/inch conversion which is usually 90. I’ve found that changing that value to 96 makes my parts load the right size


#8

you scale it before you create the g-code, either in the CAD stage or the CAM
stage (usually in the CAD stage), makercam is the CAM stage.

David Lang


#9

This is one of the hardest things about makercam. When you first start it, go to Edit>>Edit Preferences and change the first value to 96.

There is also a scaling function within makercam under Edit>>Scale Selected. You then select a percentage to increase the image by. If you use the background and some generated shapes in makercam, you can get a pretty good approximation of the end size.


#10

I am trying to cut discs for a sharpie holder to test tool paths on paper before making dust.

I needed to cut discs with an OD of 3.625". they turned out about 3.3".

I drew them in AutoCAD and saved them as Autocad 2000 DXF files. I then used Convertio to create the SVG file. When I cut the parts I had not changed the makercam Edit>>Edit Preferences from 72 to 96.

After reading this I went back and tested changing the px/inch in makercam and then loaded the files a few times with different combinations in the px/inch field and the overlay of the svg on the makercam grid shows no changes.

The ratio between the default 72 px/inch and 96 does match the amount of error I have either.

I also verified that I did actually draw 3.625" circles in AutoCAD.

What am I overlooking?


#11

are you cutting inside or outside profiles… that looks like a bit diameter offset.


#12

Yes I have the proper inside/outside selections made. The hole for the sharpie in the center of the disc was small by the same percentage. I have applied a scale factor of 109.8484 in makercam and am just about to make a cut.

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#13

I too was going to make a sharpie holder for my router but instead I bought mini sharpies and put a little electric tape around it to fit snuggly in router and it works perfectly.


#14

Well the cut is nearly the proper size. I have issues to work out as my circle is out by .070" from the small to large measurement of the oval. I need work on that, which will require moving to a different thread for help.

I think I will put a sharpie in the tool socket also. Thanks, garru2.

Tony