Lead-Ins and Lead-Outs
For proper machining of a contour, the laser should pierce the material outside of the cutting path and join the contour as a lead-in. At the end of a contour the laser can be lead from the contour with a lead-out. The optimal lengths and radius of leads depend on material and thickness.
Automatic Leads Function
Select the contours, and then select the command LeadLine in Home.
In the pop-up dialog, you can set geometry for lead-ins and lead-outs, set positions to place leads, set types of contours to place leads onto, and set whether to check and correct geometry of leads automatically. Click on OK, the software will place leads on contours according to the settings automatically.
Leads are shown in white, can be distinguished easily from the original contours, and can not be selected separately without the originals.
The picture below shows a different result on the same part with the option Change type, keep position selected and the option Check leadline unchecked. In this result, the lead-ins are placed to the original start positions of the contours and the lead-ins on the two small circles are longer than their radius, not corrected automatically.
The option Type, Angle, Length and Radius specify the geometry of lead-ins and lead-outs.
|Machining begins or ends directly on the contour without lead-in or lead-out.
|A straight line leads in to or out from the contour.
|An arc leads in to or out from the contour.
|Line + Arc
|A straight line and then an arc lead in to the contour, or an arc and then a straight line lead out from the contour.
For the type Line, the option Angle specifies the angle between the lead line and the tangent of the contour at the lead position, the option Length specifies the length of the lead line.
For the type Line + Arc, the option Angle and Length mean exact the same. And a lead arc is defined with its radius specified in the option Radius, and being tangential with both the lead line and the contour at the same time.
On the other hand, for the type Arc, the option Angle actually specifies the angle between the chord of the lead arc and the tangent of the contour at the lead position, the option Length specifies the length of the chord. In addition, the lead arc is fully defined with being tangential with the contour.
There is an exception, a lead-in to the start point of a drawing element (a line or a curve) which is not tangential with the one ahead of it will be set to the type Line regardless of the type you set. The software will try to set it to be tangential with the drawing element first, and then set it to be along with the midline of the corner if failed.
If you are not happy with the leads and want to make a change, just select the contours and select the command LeadLine again, and give it a try with different settings.
If you want to delete the leads, select the contours and then select the command Clear Leadline in Home>Clear.
Sometimes, with the option Check leadline checked in the dialog, if the software finds something wrong with the leads but cannot correct them fully automatically, it will mark them with red frames and prompt you a dialog which asks for your opinions for correction. If the errors cannot be corrected in this way, then you need to rework on the leads with different settings or fully by hand.
If the option Check leadline is not checked when setting leads, you can select the command Check Leadlines in the pulldown-menu Home>LeadLine to do the same thing and the software will react in exact the same way as above if it finds errors.
Set Leads by Hand
Sometimes, the positions to lead in or lead out is not as you wish or the leads interfere with the contours. In these cases, you can move the leads by specifying the lead positions by hand.
Select the command Start Position in Home and then click on the contour to specify the new start position. In this way, the lead will keep its geometry except the lead position.
And, you can fully specify a new lead-in by this function. Select the command and click on a position out of the contour, then click on the contour to set a lead-in line there. You can only set lead-ins with type Line in this way.
Here, we would like to mention a group of functions which are closely related to the start position of a contour.
By default, the start and end points of a closed contour are at the same position, we call it "seal". Sometimes, it is good to add some small microjoints to prevent parts from falling out or hanging on while machining, refer to Microjoints for more information.
If there is only a single microjoint to add, you can just set a gap at the start position instead of using the more complex microjoint function.
Select the contours and select the command Gap from the pulldown-menu in Home, then set gap size in the pop-up dialog. The contours are still considered closed after being set a gap on.
The gap will stick to the start position when a change made by the start position function or by setting a lead automatically.
The seal function is to remove the gaps which are set by the gap function. The over function is to set over-cuts which may result in more smooth edges. The multi-cut function is also for improving edges by cutting more than one times.
Finally, make sure to apply this group of functions in the drawing window, they are not supported in the part library and the nest results.