Lead-Ins and Lead-Outs in CamDRAW

A lead is an extra piece of path added at the start or end of a contour, so the tool enters and leaves away from the finished edge. On plasma and laser work it moves the pierce mark off the visible part. On milling it removes the plunge mark from the contour itself.

Where the settings are

The Leads & Transitions section appears in contour milling and in contour cutting for laser, plasma and waterjet. It is collapsed by default: click the header in the operation window to expand it.

Defaults for a tool can also be stored in the tool library, on the Leads tab, so that a tool you always use with a tangential lead brings its own values with it.

The fields

Position places the lead along a closed contour as a percentage. 0 is the start of the contour, 100 the end. Moving it is how you keep the entry point away from a corner or a visible face.

Hold tool down keeps the tool down when moving to the next cutting plane instead of retracting to the safety height. It applies only within the same contour and saves time on multi-pass work. Be careful on open contours: with this active, start and end points are approached directly, without a safety height.

Lead-In switches the entry on for the selected contours.

Tangential makes the entry tangential, consisting of an arc followed by a straight segment. Switched off, the lead is purely linear.

Lead-In radius is the radius of that arc.

Lead-In sweeping angle is the angle at which the linear part meets the contour.

Lead-In distance is the length of the straight segment.

Turn over Lead-In flips the lead to the other side, rotated 180 degrees. Use it when the lead would otherwise run into material you are keeping.

Lead-Out switches the exit on.

Like Lead-In mirrors the entry settings onto the exit. Switch it off and the exit gets its own independent radius, angle and distance.

Tangential or linear

Tangential approaches the contour along a curve, so the tool is already moving in the direction of the cut when it arrives. This gives the cleanest result and is the usual choice for milling and for visible edges.

Linear approaches in a straight line at the sweeping angle you set. Simpler, shorter, and adequate for plasma work where the edge quality at the entry matters less than getting the pierce away from the part.

Inside and outside contours

A lead has to have somewhere to go. On an outside contour it extends away from the part into waste material. On an inside contour it has to fit within the opening.

On small holes there may not be room for a tangential lead with a large radius. If the preview shows the lead cutting into the part, reduce the radius and distance, or use Turn over Lead-In.

Checking the result

The preview on the CorelDRAW page updates as you change values, so the effect is visible immediately.

After generating the program, the 3D view in the NC program section shows the finished paths, with cutting moves in blue and rapid moves in red. A lead running through material you meant to keep is obvious there.

Combining with tabs

On cutting operations, leads work together with material tabs. Tabs interrupt the contour to hold the part in the sheet, and the lead handles where the cut begins. Setting both is normal on laser and waterjet work.