How You Can Edit on the Fly with Mastercam Model Prep

We have come a long way since writing G-code manually, shaving hours off of programming and machine time. But, every now and then, even a solid model can take valuable time to modify, especially if the solid was imported from a CAD system that is not directly compatible with the CAM software. The clock ticks loudly when you need to create a whole new wireframe or solid to perform a minor tweak that should take minutes. Recognizing this, we incorporated features into Mastercam X7 that allow for the direct editing of solid models in Mastercam Solids and continue to improve this functionality.

Since Mastercam X8, these capabilities were expanded and organized under the Model Prep menu. Programmers can create and edit solid models – both old and new. A “history tree” lists the procedures that generate a solid model, allowing the programmer to edit any of the steps; you can move, delete, and suppress any part of the model. All direct editing functions remove this history, making it easier to edit a solid model without having to toggle back and forth between an “operations” screen and the model screen. However, clicking Undo restores the history as it was before the direct editing function.

In Mastercam 2019, three functions have been added/improved on the Model Prep tab: Align to Plane, Align to Face, and Align to Z. All three are designed to simplify the editing process and shave additional programming time.

Align to Plane allows you to quickly prepare a solid body for machining by positioning it in line with a specific plane. The solid and additional selected geometry can be moved to align with an existing plane. A new work coordinate system (WCS) based on a selected face of the solid can be created, which is especially helpful when a solid must be aligned to an entity that must remain in a particular orientation.

Solid Position has been renamed Align to Face and is easier to use. Selected faces of two solids can still be mated, but the edges of the solids that you mate can also be aligned.

Align Solid Body, which was previously on the Turning tab, has been renamed Align to Z and is now located on the Model Prep tab. Align to Z can be used to select the cylindrical face or edge of a solid body and either create a new WCS or align the solid body to the Z-axis of the current C-plane, as if it was being mounted in a lathe chuck.

Model Prep continues to be one of the favorite Mastercam features among programmers. Here’s why:

Push/Pull allows you to offset faces or push edges into fillets. Vinny Decker, CNC Programmer at Oldenburg Metal Tech, Inc. (Saukville, WI), uses it to close 3D surfaces and fill holes. “A couple of years ago, I might not have been able to close up a surface or fill in holes on a 3D surface. At that time, I would have to go to our designers and ask them to create a separate model without the holes in order to run 3D paths on it.”

Decker shares that 99 percent of the time he can suppress any feature on the solid model he chooses. He can extend 3D surfaces, move them up and down to add more clearance, or add more stock if necessary. “I don’t really touch surface modeling anymore with Model Prep features.”

By eliminating the need to create a separate surface model, he saves anywhere from five seconds to an hour in programming time.

Move works with faces and allows you to translate or rotate them on the solid body. It can be used to move or copy faces or to add draft. Solid bodies reflecting any changes can be saved as stock models. When Achates Power (San Diego, CA) prototyped the parts for its green internal combustion engine featuring an opposed piston design, machining complex, hard-to-reach geometries proved to be a challenge. In particular were the cylinder liners along which the pistons ride, each featuring hundreds of pegs and grooves. Ultimately, there were many toolpaths and additional geometry that had to be created as well as transformed, translated, rotated, and mirrored toolpaths.

Shop manager Sergio Ramirez shares, “Mastercam provides a really good way of seeing your parent stock or the stuff that you’re cutting, so we are able to follow the process of a piston or liner or other parts because we have updated models for each step of the process, and that has been really helpful for us when programming.”

Split literally splits a solid face into multiple faces that can be used with Move or Push/Pull, in either wireframe or flowline formats. Wireframe projects wireframe geometry into a face to form new edges and faces. Flowline, or UV, splits a face along its UV flowlines. An example of how Split can save a shop considerable time and trouble involves the reengineering of an aerospace part from scratch – no print, no solid model. The customer wanted to take an extension off the part and then build a new one from scratch.

Oldenburg Tech Metal’s Machine Shop Crew
Toolmaker Brian Zylka, CNC Department Manager Rob Kerfscher, CNC Coordinator Mike Muecke, CNC Department Machinist Matt Dornacker, Lathe Apprentice Jason Gonzales and CNC Machinist TJ Schimke

Engineers and machinists from Waco, TX-based Kormachine worked together to reverse the dimensions, pulling them off as best they could, because the original part was warped and cracked; bent and distressed in some places. They built the part from the ground up, drafting a new solid model in SOLIDWORKS®, verifying it, and sending it out for approvals. In order to get this part to the customer in two weeks, they performed a lot of model drafting using Model Prep, printing, and then running the actual toolpath itself.

According to owner Colter Kaspar, they broke the toolpaths into pieces and parts and put them back together again to see the whole. “We can build our stock models from raw materials, and then we can take stuff off or add it as needed.”

Simplify, which allows you to simplify a body and combine faces on a case-by-case basis by selecting faces or edges, provides more control over the solid model and customizing toolpaths.

Remote valving housing. More than 98% material removal.

David Gilbert, whose one-man shop specializes in making geometrically complex lightweight racing car suspension parts loves the flexibility Mastercam Solids and Model Prep provide him when having to choose different toolpaths for the same part. “With complex shapes I can’t simply pick a toolpath type and go with it. I essentially break the part into several segments and use different toolpath strategies for the different segments,” said Gilbert. “None of these parts are simple, even the ones that appear so.”

The ability to edit a solid model on the fly saves programmers valuable time when lead times are short. Gilbert is presented with new racecar designs during the winter months with lead times of five weeks or less. Oldenburg’s Decker saves anywhere from five seconds to an hour in programming time because there is no need to create a separate surface model for modifications.

To learn more about Model Prep and other time-saving benefits of our integrated CAD/CAM software, contact your authorized Mastercam Reseller today.