Introduction

In this article we give a comprehensive outline of the most important features of an acceptable CAM software co-operating with any CNC equipment controlling Plasma or Laser Cutting processes. Anything less would render the operator's control over any sheet forming job questionable and the results less satisfactory than otherwise expected.

The features that the demanding manufacturer should insist on are the following:


1. Saving and loading of any Cutting Layouts we have produced.

2. Creating Materials and Plates lists to be used on the cutting table.
Creating the Material list with Type, Thickness, Specific Weight (weight per volume unit), Kerf for the material in question, Cutting rate (Feed Rate) and Piercing. This Catalogue should then link to the Plates Catalogue to provide material sheet info for each specific sheet (plate) contained in it, along with such info as the sheet Dimensions (Length, Width, Thickness) to be taken into consideration when the Parts are imported and the final CNC code is generated.

3. Part Import from a file in the CAD software or from the CAM Parts List.
Preview of the Cutting Layout and its dimensions before it is imported into the plate.
Option to add the actual part to the programme's Parts list for future use.

4. Part Placement

Features:

• Setting priorities in the job list queue to our judgement
• Sorting as per their area
• Number of the copies to be cut
• Printouts of selected parts' properties
• Automatic Part placement
• Manual Part Placement
• Rotation of the part(s), optional rotation steps (degrees)
• Zooming of the plate with the placed parts
• Moving of the whole plate to be able to see details
• Part transfer and mirroring along optional axes
• Changing of the Lead In/Out of any part(s) at any time during the placement process
• Automatic placement of only one or all of the copies of the part in the catalogue selected
• Automatic placement of all copies of all the parts in the catalogue
• Automatic nesting of the parts placed in the plate
• Setting Minimum Part to Part distance
• Setting Minimum Part to Lead In or Lead Out Distance
• Setting the Number of Torches, for the programme to adjust the percentage of the sheet (plate) to be used by each torch
• Very advanced management of the parts placed in the plate: We should be able to set the rotation angle of a part in the process of automatic nesting in the plate, while automatically testing for its optimal placing
• Auto or Manual Search Step; option to allow for Top Placement to save on raw materials.

5. Routing

Features:

• Torch starting and parking point
• Continuous or Random cutting succession to avoid eventual overheating of the plate
• Manual Routing option replaceable at any point with the automatic one
• Deletion of the actual Manual Routing step by step or as a whole with one mouse click
• Restoration of a routing accidentally deleted
• Automatic setting of the Cut Route for the parts placed in the plate
• Kerf Readjustment before G-Code generation
• After the Code is generated, we should still be able zoom in to cheque its correctness
• Exact on-the-plate simulation of the final cut showing Kerf in its actual thickness
• Print-out of the current job regardless the stage of the nesting procedure
• Label printout for the placed parts with their characteristics. Printable also on self-adhesive A4 sheets
• Transformation of short successive straight lines into an arc (useful for PLT files)
• Controlled addition of cutting Tabs to objects with very long sides, for them to remain connected to the plate and not get lost in the scrap
• Adding of a cutting Tab to the end of a small Part’s perimetre for it to remain attached to the plate and not get lost in the scrap
• Option to add loops to angles to avoid over-melting of the material
• Advanced built-in options related to Outer and Inner Path settings (Lead In and Lead Out Types, Lead In and Lead Out Path length, Lead In and Lead Out speed and Path cutting direction
• Special care of Cutting of Small Holes that there are usually on many Parts, addressing some specific problems related to their proper cutting...
  They should include:
• Dealing with Small holes as if they were Inner Paths
• Threshold Diametre (Determining the largest diametre of a hole for it to be considered a Small Hole and be cut according to the Inner Path settings)
• Start from the Hole Centre (Lead In Length equals the radius of the circle)
• Lead In Type (Here we determine the cutting head’s approach path; optional circular line, very useful to cut circles)
• Lead Out Type (The type of the cutting head’s moving away from the Drawing)
• Lead In and Out path length (This determines the distance to or from the objects perimetre that Piercing will take place)
• Lead in and Lead Out Speed (Lead In and Lead Out feed rate)

6. Layer Configuration
This part of the programme is perhaps the most important one; here the user can determine:

• Whether the machine will function as an engraver or a cutter
• Whether Open Drawings can be imported and cut
• Whether it is possible to Import Parts with sides which are not supposed to be cut
• Whether we can have common cuts, that is process the edges of two adjoining parts with the same cut, with the purpose of saving material, cutting gas and time.
  
  Features:
• Defining the layers in DXF and PLT file types
• Enabling Layer Filtre, so that multi-layered parts can be imported to our programme
• Configuring Cutting and Non Cut Layers
• Configuring Open Contour Layers, to deal with Open Drawings. We can therefore import Open Drawings and cut them as any other Part
• Configuring of Marking Layers; this is especially useful to laser cutting machines, where also metal marking, or even marking on any other cuttable material, is possible
• Adding non-cut routes to create tabs to handle cutting of very small and very long parts
• Kerf Compensation: This is an operator adjustable dimension, which can be altered at any time; it is the amount of cutting path offset required to compensate for the material removed by the cutting process.

7. Print Settings
The Print settings that a CAM software should allow for are the following:

• Parts in the Plate colour; the colour of the parts in the Plate as shown in a Printout of the Nesting
• Marking colour of all commands in Marking Printοuts
• Open Contour colour in all Printouts
• Parts colour when printed in detail
• Text colour in all Printouts
• Font Colour: When we place a large number of Parts in the plate it is usually difficult to recognise the Parts; we should therefore be allowed to print a number on the part, same as the number of any part in the Part Catalogue so that they are more easily recognizable
• Font Size of the parts-on-the-plate numbers (see Font Colour above)
• The colour of the commands that are not going to be cut; here we should be able to omit printing these commands

8. System Settings
Finally, there are settings that have to do with the System itself. All software feature similar settings, CAM, Colour and Language settings.

CΑΜ Settings would be related to

• 1. Plotter Units for PLT type files
• 2. PLT file parametres
• a. Threshold Line = Μaximum Length of straight lines to be converted to Arc
• b. Threshold Angle = Maximum angle formed by straight lines and
• c. Arc Tolerance = Maximum distance between the centres of two consecutive similar arcs to be considered as one)
• 3. Join Length (Maximum Gap allowed between two continuous points
• 4. Moving Step (of any Part in the plate while placing)

Colour Settings would be related to Plate colouring, Selected Part, Dropped Part, Error Part, Plate Border, Non Cut, Open Contour and Marking colours.

Set Language Settings would determine the Language in the Forms And the Printouts.