Moldmaking Q&A

Smarter toolpaths, premachining verification can reduce both time and errors

May 4, 2011

Programming complete toolpaths quickly is a must for moldmakers.

Precise models give a representation of the material still remaining on the part and are used to ensure that the cutter is never asked to remove more material than it can safely cut.

To be competitive, today’s mold designers must complete their work in the shortest time possible. When your production runs are in the single digits, any delays cost money. Canadian Industrial Machinery (CIM) asked Ben Mund, marketing manager for CNC Software Inc., for his opinions. Here’s what he had to say.

CIM: How important is reducing programming time to today’s moldmakers?

Mund: Reduction in programming time is always important, but it becomes more so the fewer parts you produce from a single program. If someone is producing a job run of 10,000 parts, they usually don’t mind spending a little extra time to set up the perfect program that shaves every possible fraction of a second from the machining time. With one- or two-off pieces such as a mold, however, you see much greater gains from being able to program a part quickly.

CIM: What software techniques reduce this time?

Mund: Smarter toolpaths. That answer may seem simple, but it’s absolutely true. More and more CAM programming techniques involve toolpaths that evaluate the part and change cutting strategy on-the-fly. This can take a part that may have previously needed eight or 10 toolpaths down to one or two toolpaths.

CIM: How is new software best implemented?

Mund: First you have to understand their needs, [and] often these are extremely practical. People want to program complete toolpaths faster, spend less time on the machine, or both. We’ve found the best method of showing gains from new software is just as practical — we compare final cut times and finishes on the same part, using traditional toolpaths and then newer toolpaths. It’s also effective to run side-by-side video so programmers can see exactly what the tool motion is.  It’s important to provide in-depth and direct information so they can judge for themselves what the impact would be for them.

CIM: Can time spent on tool and machining parameter selection be reduced?

Mund: Absolutely. As an example, the current work we’re doing with Iscar allows the user to simply select an Iscar tool, and Mastercam will preload the optimal settings to make sure the tool cuts at peak performance.

CIM: Can rest roughing and rest finishing time be reduced at the programming stage?

Mund: Yes. Automation helps with both of these at the programming stage. Many CAM systems make rest material removal programming extremely simple and automatic.

CIM: Is it necessary to create accurate models after each stage of machining?

Mund: Yes. Having the CAM software create internal models of what has been cut so far is extremely important. It relates to the earlier question about rest machining. As the software moves forward from, say, a 3-D roughing pass to rough rest pass, it can provide much more automation and accuracy if it already knows exactly where extra material exists.

CIM: What is the relationship between toolpath generation and machining strategy?

Mund: Some toolpath strategies that get developed are a huge leap forward in material removal and improved cycle times. Since companies are always looking to increase their profits by reducing their cycle times and improving surface finish, these advancements in toolpath technology appeal to our customers. New machining strategies can directly relate to an increase in profits. 

CIM: How important is it for today’s software to keep pace with advanced machine tools?

Mund: The entire manufacturing process is only as strong as its weakest link. If you are using advanced CNC software to drive an older CNC machine, you are only going to get the maximum out of what the machine can offer. 

The same can be said for advanced machines and tooling. If the software is not kept up-to-date with the other technology in the shop, it becomes the weakest link in the manufacturing process.  For this reason, it is crucial that the software be able to handle the latest and greatest advancements in machining technology, whether that’s advancements in tooling or advancements in machine motion.

CIM: How can the goal of maximum metal removal be achieved?

Mund: This is the result of collaboration between machine tool builders, cutting tool manufacturers, and software developers. 

Based on the individual developments, for example, the creation of a cutting tool that is optimized for specific cutting parameters, software can be developed to accommodate these advancements.  The end result is a partnership that takes advantage of independent developments and produces tools and features that allow users to optimize their manufacturing process.

CIM: How can cycle times be reduced because of this?

Mund: If a tool has been developed to be at its most efficient when cutting with a certain set of parameters, the software will identify this and update the machining values accordingly to minimize cycle times.

CIM: Lastly, is it necessary to verify the toolpath before a part is cut?

Mund: This is extremely important.  In many cases, issues will arise that the programmer is not even aware of.  For example, a clamp could be in the way or a retract height was incorrectly entered. By catching these issues before a single chip is made, you can save hundreds, possibly thousands, of dollars.

For more information, visit www.mastercam.com.