This command add toolpath to parts that should be cut all the way around.
Automatic lead
When this option is activated then leads and piercing types are automatically calculated by an ILISP script. The script automatically generates the optimal piercing type and lead geometry depending on material, thickness, and the geometry of the part. When the Automatic lead is activated then you cannot select your own lead geometry.
No tab
When this option is activated, the jet will cut all the way around the geometry.
This option is perfect on large part that do not moves or falling in the tank when the cut is finish.
Add Tab
Tabs are used on small parts to avoid them to fall in the tank and to avoid that the parts get dammed at the end of the cut.
Set the Tab width to a distance large enough to fix the part to the material. The value will be stored on actual material and thickness that you are using.
The picture above shows lead-ins with tabs that fix the part to the material. The cutting is stopped before the part is finish.
Auto tab
If you select the Auto tab option, then the LISP script will automatically switch between No tab and Add tab. This is depending on the size of the part and the layout on the cutting table.
Lead settings
By clicking on the "Lead settings" button following dialog is shown.
Lead length %
The fastest way of piercing thru the material is to use linear piercing. In linear piercing there is no delay after jet on, the jet will cut through the material during the leadin movement. The value is in percent of thickness. Normal value is 12-15 percent of the thickness. Example: 10 mm thickness will have a lead length of 1.5 + half maximum tool diameter.
Add tab on small x-size
If this checkbox is activated, the function will add a tab if the size of the part in X direction is smaller than the entered value.
Add tab on small y-size
If this checkbox is activated, the function will add a tab if the size of the part in Y direction is smaller than the entered value.
On this example there are some parts that are smaller than 35 mm in X. It’s a high risk that those parts will fall in the tank. These parts will have a tab of 0.3 mm. One of the holes has a part inside. This will also be tabbed to avoid fall into the tank.
Tool radius compensation (kerf)
When you are using kerf compensation left or right then the trajectory will be moved outside an external geometry and inside an internal geometry (Se picture A above)
If you select the left option, then the cutting direction will be CW for external geometry and CCW for internal geometry. If you select the right option, then the cutting direction will be opposite. In the most CNC controllers the Left option is G41 and right option G42.
If you cut with no compensation, then the parts will have wrong dimension.
For flat 2D parts the tool radius compensation can be added in IGEMS or in the CNC controller. Most users prefer to add the kerf in the CNC since the dimension then can be adjusted by the operator.
You can choose one following options for External and Internal geometries.
- Tool on left
- Tool on right
- No compensation
The direction CW or CCW is depending on if it's an external or an internal geometry.
Lead selection
It is possible to predefine leads-in and leadouts and create a library of leads that can be selected in the lead lists.
IGEMS can use different leads for external and internal geometries. It is also possible to use a special lead if the lead is placed in a sharp corner. When you place a lead then it is collision detected against all other parts if there is a collision with other parts then the alternative lead will be used.
Lead 1 is an external lead, lead 2 is an internal lead, lead 3 is a corner lead and lead 4 is an alternative lead.
Lead 4 seems to damage the material?
No, this is a blind lead and the lead in is not used for cutting. Read more in "Lead definitions"
You can read more about the different piercing types and leads on "Lead definitions"
Favorites
This was a feature we developed before we have the automatic leads. It will probably be removed in future versions of IGEMS
Multi-mode
When using "Multi" mode you can select all parts at the same time. The function will sort the internal cutting order of in all parts. It will place the leads at good positions on the geometries. It will select the defined leads depending on the geometries. To be able to do this it need some rules.
To execute the multi command that places the leads automatically press the Multi button.
Sorting
The name of the 6-sorting algorithm is quit self-describing.
Closest
Closest is optimized to give the shortest rapid distance between the parts.
Zig zag
Zig zag has an option dialog to select different zig zag methods. There is a preview in this dialog that are quit self-describing.
Left to right
Will start at the very left hole and continue in right direction.
Right to left
This sort in opposite direction as left to right.
Spread
Spread will take the order very randomly, it's developed for plasma cutting to spread out the heat over larger area.
None
Will take the holes in the same order as the holes was drawn.
On the picture above the sorting order is set to closest.
Contours
This setting controls which contours the leads should be attached to.
Add new and replace existing
This method adds new and replaces all existing leads on the selected parts. Do not use this option if some leads are placed with other commands that shouldn't change.
Replace existing
In parts with no leads, this choice will not produce anything since it replaces existing leads with the defined leads. This method uses the same lead positions as the already existing leads.
Add new
This method adds leads on contours that have no lead. Use this method when leads were placed by other commands.
Individual
Use this method to select contours transparently inside parts. See picture below.
This method adds new and replaces existing leads.
Placement
It is possible to set rules where to place the leads both for external and internal geometries.
We recommend that in all normal cases use the option "Auto" since this gives the shortest trajectory.
Prefer corner
With this option, the leads will be placed in sharp corners. This option is stronger than the other placement rules.
Connect to part
If the toolpath is not connected to the part we also call this disconnected.
This option is also available in other commands. When the toolpath is connected then it is bound to the part. When the part is moved, then the toolpath should be moved. A toolpath that handles more than one part cannot be connected, for example "Common cutline". In the example below the same toolpaths are used for 10 parts.
By deactivating this checkbox, a toolpath is created that is disconnected from the parts.
What can a disconnected toolpath be used for?
You can then create several toolpaths on the same part in order to assign different tools on the same parts.
Only the internal cut is in the example above. The contours on the left side (A) are connected to the part, and the contours on the right side (B) are not. It is now possible to assign two different tools to these two geometries.
Collision detection
This is the normal stage. In this case it's impossible to place a lead at a position that can damage other parts. If this checkbox is deactivated, then you can place the lead at any position even if its damage other parts.
All holes first
To be able to use this functionality the checkbox "Connect to part" must be deactivated.
This will generate a disconnected toolpath and all holes are cut before the two external geometries.
Single mode
Use the "Single" button to manually attach leads to geometries.
Open the file "Single.dig" located in the "Sample directory"
Attach the leads on desired positions by clicking the "Single" button. Start with internal geometries and take the external geometry as the last. The geometries on the part will be cut in the order inputted.
Change position of leads
Change the position of the lead by re-clicking on the same contour.
Can I change the cutting order?
In the "Edit toolpath" command you can change the order.
You can also delete all leads and place them again.
Not in the "Single" mode. This is done in "Multi" mode and using "Edit" toolpath.
Lead definitions
If you click on the Edit button, then following dialog will be shown.
You can add new or delete definitions you don't want by clicking on the plus or minus buttons.
1.1.6 Lead preview
It can be difficult to exactly understand the effect of the different lead settings. On this preview you can zoom and pan. You can see the result when the settings are applied on different kind of geometries or when you change cutting direction CCW or CW. The red objects are the leadin, the blue is the leadout.
Piercing
The piercing controls how the jet make the start through the material. The following methods are supported:
Blind lead
- Rapid to point (A)
- The kerf (G41/G42) is activated, and the jet then makes a linear movement to point (B). Note! the jet is still off.
- At this point (B) the jet is opened and without any delays the geometry starts to cut.
- After some distance (C) the jet has cuts through the material.
Important!
It must be an overcut when using blind leads. The overcut distance must be at least the distance between (B) and (C). When using "Automatic leads" the overcut distance is calculated automatically.
In AWJ cutting this piercing method can be used on all material that can be pierced with high pressure. The benefit with this method is that it does not require any leadin that can damage parts and material. It also gives an excellent result. Note! Not all CNC-controllers can support this method.
Linear piercing
This is the movements:
- Rapid to point (A)
- Jet is opened and then kerf compensation (G41/G42) is activated
- The jet continues to point (B).
- The speed used for the leadin is the X-fine speed. If the distance between point (A) and (B) is so short that the jet cannot cut through the material, then the jet goes back and forth between (A) and (B) as many times as needed.
Except for Blind lead the linear piercing is the fastest way to cut through the material.
The length of the linear piercing can be set individually on each material and thickness. Read more about the linear piercing on the material settings on page 226.
Advice
The length of the linear piercing should be 12-15% of the material thickness plus half of the tool diameter.
When using "Automatic leads" the linear piercing length is calculated automatically.
Stationary piercing
This is the movements:
- Rapid to point (A)
- At this point the jet is open and remains there until the jet has cut through the material.
- The kerf compensation (G41/G42) is activated
- The jet continues to point (B) and then continue to cut the geometry.
Advice
This piercing method takes the longest time and we do not recommend using it. It is supported for compatibility reasons. The stationary piercing time can be set on each material (see page 225 for more information).
Circular piercing
This is the movements:
- Rapid to point (A)
- At this point the jet is opened and then it goes to point (B).
- The jet now makes circular movements around point (A) until the jet has cut through the material.
- The kerf compensation (G41/G42) is activated
- The jet continues to point (C) and then continue to cut the geometry.
Advice
This is an excellent method to use on thick material.
It is also the best method to use for Low pressure piercing sine it reduces the risk of the material cracking.
All parameters like the radius, speed of the movement and time can be set individually for each material.
Drilling
This method is only possible if the machine is equipped with a drilling unit.
All drilling will be performed sheetwise or partwise before the cutting.
If the machine has no drilling unit, then IGEMS uses circular piercing. Set drilling parameters on the "material setup" and control the drilling sequences in the "Strategy" command.
Air start
This method is used when a piercing is not needed. For example: Starting outside a sheet or in an existing hole. This method is automatically used for cutting when the start hole has been drilled or pre-pierced.
User piercing
This method is specified in the postprocessor for customization of a special process. Do not use this method if the postprocessor is not developed for this method.
Leadin
Dynamic lead
When the Dynamic lead is activated the linear length of the leadin is variable. In the picture above length is between 3 to 20 millimeters.
If you make a piercing in a cracking material, then it's a risk that the piercing process will damage the material on the bottom side. Of that reason it's good to have the leadin as long as possible.
When you click on the dot button you can enter minimum and maximum lead distances.
The dynamic lead always tries to place the piecing as long as possible away from the part. But no longer than the maximum distance.
The Dynamic leads are often used together with Circular piecing and Low-pressure piercing.
Advice
Try to use "Automatic lead". It will automatically use this setting if the material should be pierced with low pressure.
Length
This is the linear first portion of the lead. The length should be at least half of the value specified as "Maximum tool diameter"
Radius
Do never specify a radius that is smaller than the "Maximum tool diameter". If you do so then you will probably get an error on some CNC-controllers.
Advice
We don't recommend using radius on the leadins in waterjet cutting, but some users need this option.
Angle
This controls the angle of the leadin.
Please check the "Lead preview" when you play with different parameters.
Leadout
These values are applied on the leadout. Please look at the "Lead preview" to see what's happen when you play with these parameters.
Overcut and gap
Use negative overcut if you want to make a gap between the leadin and the leadout.
On the picture above you can see the gap as the yellow line between the red and blue lead.
Use a positive overcut if you want to cut the entry part of the geometry two times.
Advice
When using "Automatic leads" then all parameters are calculated automatically.
Dimple
The dimple option will remove more material on the part close at the lead position.