Profile

A profile cuts along a closed contour:

• outside it, to cut a part out;
• inside it, to cut a hole;
• on the line.

Select the contours, then Profile (ribbon, OPERATION). See Side and direction and Depths and oversize for what every profile shares.

Open contours (centre lines, construction lines) in the selection are skipped with a note. To cut along an open line, use Follow path.

The spiral ramp

A profile always goes down as one forward spiral along the contour: no plunge into the part, so there is no plunge mark, and any endmill can cut it, centre-cutting or not. In the operation’s Cut settings, right after the step down, the ramp angle (3° by default, at most 30°) says how steeply:

• each pass goes down at the ramp angle, then runs level for the rest of its lap, and never more than one step down per lap (on small contours the angle alone decides, so a pass may take more than one lap);
• at the end only the ramped stretch is cut level, so the floor is flat;
• the tool rises out along the cut path, never back and forth.

A steeper angle makes the ramp shorter: 4 mm at 3° takes 76 mm of contour, at 10° 23 mm. In the file the angle is ramp_angle, in radians.

Holding the part

Holding chooses how a part that is cut out stays in place: none, tabs, onion skin, or onion skin and tabs. Only the chosen kind’s settings show.

• Tabs keep the part attached at a few points until you cut it free.
• An onion skin holds it all round during the roughing; the last lap then cuts through the skin, and the part is free during that lap.
• Both: the skin holds it all round during the roughing, and the tabs keep it from moving while the last lap cuts through the skin.

Tabs

Tabs are bridges of material left at the bottom of the cut, so a part cut out doesn’t come loose on the last pass.

• Placement: tabs slide off corners to straight stretches, by up to a quarter of their spacing.
• Spacing: they keep a tool diameter from each other and from the start of the contour.
• Shown highlighted on the canvas.

Tabs placed by hand

You can put a contour’s tabs where you want them instead. Select the profile after generating: each tab has a small square on the canvas, hollow where Chipload spaced it and filled where you placed it.

• Drag a tab along its contour; it generates again when you let go.
• Right-click a tab to remove it, or to space that contour’s tabs evenly again.
• Right-click the contour’s toolpath for Add a tab here.
• Under Tabs in Properties, 5 tabs placed by hand counts them, and Reset spaces every contour’s tabs evenly again. Each change is one undo step.

On the command line, list them and add or remove one at a point on (or near) the contour:

chipload op tabs part.chipload --op 2
ring 1  (146.551, 132.176)  spaced
…
chipload op tab part.chipload --op 2 --at 162,91            # add one
chipload op tab part.chipload --op 2 --at 146.5,132 --remove
chipload op tab part.chipload --op 2 --at 162,91 --even     # this contour spaced evenly again
chipload op tab part.chipload --op 2 --reset                # every contour

• The first tab you add or remove on a contour keeps its other tabs where Chipload had put them; from then on that contour has exactly the tabs you placed, and count is for the contours you haven’t touched.
• A tab placed by hand stays where you put it, also on a corner (the report notes it).
• Generating stops, naming the tab, if two tabs come closer than their width plus two tool diameters, if a tab covers the contour’s start (move the tab or the start), or if a tab is no longer on any contour of the operation (the drawing changed).
• The points move with the drawing when you place it or move, turn or scale the drawn shape, and every copy gets them. In the file they are tabs.at, points in drawing coordinates.

Start point

Each contour’s cut starts at a point Chipload picks. To move it, select the operation, then drag the start marker along the contour on the canvas; right-click the marker to reset it. Tabs Chipload spaces move with the start; tabs placed by hand stay. In the file, starts holds the points.

Finishing pass

Finishing pass with a stock value:

• the roughing laps leave that much on the wall;
• one light lap at the wall at full depth then takes it off.

The wall comes out clean: the tool isn’t loaded on that lap, so it doesn’t deflect, and there are no step marks from the passes. The stock must be less than the tool radius.

Onion skin

Onion skin with a thickness:

• the passes stop that far above the end depth;
• one last lap cuts through the skin.

Small parts stay held until the very end, on a vacuum table or instead of tabs. The skin is at most one step down, and thinner than the tab height when there are tabs (onion skin and tabs under Holding).

Dogbones and T-bones

A round tool leaves a fillet of its radius in every inside corner, so a square tenon won’t go into the mortise. Corners reaches into them:

• dogbones: the tool goes into the corner along its bisector;
• T-bones: the tool goes in along the longer wall, so the notch is in the shorter wall, out of sight.

up to sets the sharpest corner angle that gets one (100° by default, so 90° corners drawn slightly off count). A corner the tool can’t reach at all (a notch narrower than the tool) is left round, with a note.

A bone that also cuts into another contour that is cut (a thin wall between this cut and another), or into another wall of its own (a short step next to the corner), is cut all the same, with a warning that names the corner: check the part there, or choose another bone for that corner. Lines that don’t count:

• lines no enabled operation cuts (construction lines, a layer nothing cuts, a disabled operation’s shapes);
• a line that meets what the operation cuts near the bone: on its own wall (a shared edge), crossing it, or, in a pocket, running into the pocket. It has been cut through there already.

Corner by corner

Any corner can have its own choice, whatever Corners says: round, dogbone, T-bone along the longer wall or T-bone along the shorter wall. It goes past up to too. So you can turn one T-bone the other way, leave out the one corner where a bone doesn’t fit, or leave Corners on round and give bones only to the corners that need them.

With the operation selected, every corner on the tool’s side has a small diamond on the canvas: filled, with the tool’s circle where its bone goes, when it gets one; hollow when it stays round; amber when the last generation’s tool couldn’t reach into it. A ring round the diamond marks a corner with its own choice. Click a diamond (or right-click it) for its menu: As the operation, Round, Dogbone, T-bone along the longer wall, T-bone along the shorter wall. Hovering an entry draws its bone; clicking it generates again. Each choice is one undo step. Under Corners in Properties, 2 corners chosen one by one counts them, and Reset gives every corner the operation’s setting again.

On the command line, list an operation’s corners and what each gets, then choose:

chipload op corners part.chipload --op 2
(11.214, 301)  90.0°  dogbone
(511.214, 301)  90.0°  dogbone
…
chipload op corner part.chipload --op 2 --at 11.214,301 --bone tbone --along shorter
chipload op corner part.chipload --op 2 --at 511.214,301 --bone none
chipload op corner part.chipload --op 2 --at 511.214,301 --as-operation   # its choice removed
chipload op corner part.chipload --op 2 --reset                           # every choice removed

A choice is kept as the corner’s point on the drawing, as start points are, and moves with the DXF when you place it. Every copy gets it. If the drawing changes so a chosen corner is gone, generating stops and says which choice to remove. The setup sheet says how many corners were chosen one by one.

In the file

"type": "profile" in the project file. Lengths are in mm, feeds in mm/min, angles in radians.