Stock and Work Coordinate System – FreeCAD CAM

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After starting a new CAM project, the settings window opens on the Setup tab.

In this tab, we determine the dimensions of the stock and the location of the coordinate system origin, I will call it the base.

As for the stock, we have several options that we can use to determining the dimensions of the stock.

The first option is the Create Box, where you can manually specify the dimensions of the stock.

We have to specify the length, width and height of the stock.

Enter, for example, As length 110, as width 60 and as height 20.

And as you can see the stock increases only one way. And this setting in most cases does not make sense. Because we usually want to machine the whole shape around. But to set the part in the middle of the stock we can click the XY in Stock button (first select the part), then the part in XY axes will be placed in the middle of the stock.

Or click Center in Stock, then the whole part will be placed in the middle of the stock.

Now let’s set the origin of the coordinate system at the top of the stock in the lower left corner.

To do this, click on the top of the stock in selected corner and click the Set Origin button.

At this point, we have symmetrical allowances for each side.

We can assume that the top wall of the stock does not require facing

And the top face of the part can be set in the Z0 coordinate.

Click on the face of the part and click the Z = 0 button.

And we will get:

But what if, for example, I would like to specify a specific allowance for each side, e.g. 2 mm allowance per side and a specific allowance at the top of the part e.g. 1 mm and 10 mm allowane at the bottom to put in a vice. Then it is worth using another option to specify the dimensions of the stock.

But first let’s check one more method of determining the stock.

This is the Create Cylinder, which means that in this case we can define the stock as a cylinder.

And the method where we can give any allowance is the Extend Model’s Bound Box.

And let’s set here allowances of two mm per side in the X and Y axes, 10 mm allowance at the bottom and 1 mm allowance at the top.

Let’s set the origin of the coordinate system in the lower left corner at the top of the part.

Ok, we have stock and work coordinate system defined.