Save Time and Money with CAD-CAM Sheet Optimizing and Nesting


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Manufacturers use CAD-CAM software because the automation saves them time, lowers cost and streamlines the machining process in a way that produces parts quicker and more efficiently. Machinists understand that the best way to improve profitability is to reduce waste. Reducing material-related expenses and cutting down on wasted materials can easily be achieved with Nesting software. Nesting produces a series of shapes in an efficient way on one or more sheets of material to determine the most amount of material that can be cut with the least amount of leftovers. Shops that run CNC Routing, Waterjet, Laser, Plasma and CNC Burning machines generally have a need to nest a series of parts on sheets of material to get the results they desire.

cad-cam sheet optimizing
CAD-CAM Software for Sheet Optimizing & Nesting
Many CNC machines allow users to cut or machine a large number of part shapes on a sheet of material. Figuring out the logistics manually would be massively time-consuming and less effective. This is where CAD-CAM’s worth is established.
 
The process is referred to as Nesting or Sheet Optimizing. A sheet of material is defined in X and Y dimensions, then a series of shapes and quantities of those shapes are applied to the material digitally. Occasionally, the operator will want to further define the angle and direction of the cutting to compensate for the grain direction of the material they are using. CAD-CAM Nesting allows users to do just that. Furthermore, CAD-CAM software lets users make adjustments by changing the Nesting parameters so they can get their desired result. Programmers can then apply tools, cutting depths and an assortment of different parameters that define the generation of Toolpath for machining.
cad-cam nesting
Nesting Wizard for CAD-CAM
The Nesting Wizard is a system that walks the programmer or CNC machinist through the process of Toolpath creation and ultimately takes the best route towards cutting your parts. Guesswork is eliminated from CAD-CAM programming and simplifies the programming process. The CAD-CAM Nesting Wizard allows the CNC programmer or CAD designer to import or draw the shapes/profiles needed for the Nesting process that will be machined in the end.
CAD-CAM software comes with a CAD design package integrated with the CAM side that allows for the importing of DXF files. These files are 2D geometry part file types. Once the user imports or draws the files, the operator will have an arrangement of Nesting features that can be accessed to program the sheet according to the specified parameters. The Nesting Wizard will provide the necessary tools to program efficiently.
 
Next, the Nesting Wizard will list each of the shapes you created and provide fields for the user to further define the number of shapes needed in the Nesting process, whether there is a part rotation or not and even provides the option of defining grain direction in jobs that take place on a wood material.
cad-cam parameters in nesting
More times than not, shapes that are machined in Nesting will require tabs between each part so they don’t completely fall loose. In the tabbing stage of the Nesting Wizard, the tab can be modified in terms of location on the part, width, length, angle, height, etc… Tabs can be applied on the inside or the outside of the part and multiple tabs can be created individually from part to part in the same job. This can be a big advantage as each part will be different when working with multiple parts.
 
Additionally, another helpful resource in the tabbing stage is to add frame thickness and a cut-off option. As the Nesting Wizard moves the user through the process, the following dialog is dedicated to the material being utilized. Multiple shapes can be used and parameters can be selected that will determine where the software begins Nesting out shapes. Options to fill up the whole sheet or not can be selected and a grain direction can be chosen along the X or Y axis. Sheet thickness can be added as well.
cad-cam part geometry
Once parameters are established, the programmer continues in the wizard by moving along to the next screen which deals with general Nesting parameters. These include cutter compensation, setting the sequence of cutting or even cutting small parts after the big parts have been machined. Next, the user sets the material approach such as clearance plane, rapid plane, feed plane & other depth settings. All machine strategies are accessed within the wizard and gives the user maximum control over the overall g-code produced. Nesting add-ons, like those from BobCAD-CAM, gives users Profile Roughing, Finishing, Engraving, Chamfer Milling and Corner Rounding (more can be added later if needed).
 
The next part of the wizard deals entirely with posting parameters like work offsets, as well as contour output using line moves or arc moves. Tool cribs, tool holders and complete tool libraries are available to pick the right tool for a machining feature in the CAM Tree section of the wizard. With different machining strategies picked by the user, there are different tools required. This is done in the tool wizard dialog. Here users can override speeds and feeds, SFM, etc…
 
The next Nesting Wizard dialog allows the programmer to set up a side allowance and an added bottom allowance to support a method known as “onion skinning”. This leaves a small amount of material at the bottom so the part does not fully separate from the sheet. Single-step cuts can be established in Z or roughing-type step downs at specific Z distances, a total depth can be set as well as the total depth of cut or automatically setting roughing passes for a profile cut that is based off a number of cuts. Set the tool entry with your wizard and establish whether it should require a ramp or plunge move. Equally as important is your Lead-In/Out cutting. Irregular shapes being nested will require different corner types while machining. Corners can vary and may be sharp, round, loop radius, loop length, triangle or have a bisect line type.
 
As you progress through the wizard, a CAM Tree within the wizard is created and visible. The user can now choose a machining sequence.cad-cam software post manager This begins the process on the CAM side to sort nested shapes in the X direction, Y direction or just the closest from shape to shape. Users can also prompt a starting direction. Upon a finishing operation being selected, the wizard will continue providing finishing parameters and determine the final g-code that gets produced. Users can exit the wizard any time to make modifications in the CAM Tree or select “compute” and all shapes will be nested and produce visible Toolpath in the CAD-CAM workspace. The CAM Tree and complete Nesting Wizard are completely accessible to make any changes to the job, tools or individual parts.
 
Simulation in CAD-CAM Nesting
Exceptional CAD-CAM software provides complete simulation capabilities so users can verify Toolpath, catch errors before they happen and visually inspect their machine or part before it reaches the shop floor. A simulation will also allow the user to more accurately predict cycle times. To give Nesting CAD-CAM software a try for yourself, download a free trial of BobNEST here.

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