Machining Efficiently

Multicore CPUs reduce toolpath calculation time in the machining of large parts.

Today’s reality is that parts must be produced faster and more cost-effectively. The latest in hardware technology increases toolpath calculation efficiency and, in doing so, increases machine utilization.

Specifically, multicore central processing units (CPUs) can give machine tool users significant productivity gains because the software can send individual parts of a lengthy calculation to separate processor cores.

“Tests conducted by Delcam on a range of strategies showed that toolpath calculations were three to four times faster compared with earlier versions on a single-core PC,” said Delcam International Marketing Manager Peter Dickin. “Further saving improvements depend heavily on hardware configuration and software.”

Another increase in speed can be achieved by using 64-bit processing rather than 32-bit processing. This additional processing power allows programmers to work with data files of almost any size. As machines become more capable of handling complex parts, model file sizes become larger. These large program files can, in turn, affect memory availability and computing speed.

“An advantage of a 64-bit operating system is the increase in memory availability. However, there isn’t much point loading a huge model if it takes ages to calculate the toolpaths,” said Dickin.

The advantage of using a multicore CPU is it makes the machining of large parts, as well as complex parts, more practical because the overall toolpath calculation time is reduced.

New software is another way to get the most out of a machine tool.

Most software developers today offer products with parallel processing capability, also called multithreading, a function in which the program performs different parts of the calculation at the same time. Now, however, background processing also is possible, which allows the programmer to prepare, calculate, and edit toolpaths in the foreground, while the software calculates other toolpaths in the background.

According to Dickin, the ability to multithread in both the foreground and background operations, in systems like Delcam’s, reduces programming time.

“Competition is tougher than ever for today’s shops, so anything that can improve productivity or machine utilization, or reduce delivery times, is important,” said Dickin. “A lot is made of competition from China and other countries with lower labor costs; however, the real competition for most machine shops is really the shop down the road that has faster computers, more powerful software, more skillful operators, and newer machine tools.”

As parts and machine tools become more sophisticated, accurate simulation has become more and more important.

Nonproductive Time

Reducing air cutting is an effective way to reduce nonproductive time on a machine tool. Software packages that use stock models to represent the material remaining from the original block are most beneficial for reducing air cutting.

Toolpaths in this setup are limited to areas where material still remains, rather than the entire part. While there will always be a need for the cutter to move around the part between cutting moves, such software packages can minimize this time by increasing the speed of these movements automatically.

Another time-waster that must be eliminated is attempting to program parts that are difficult, or even impossible, to machine because of poor design.

“Often there is a difference in what the design engineers see and what a manufacturing engineer has to make,” explained Dickin. “Proper design is all about achieving the perfect balance of form and function. The key to a good software program is the ability to achieve this balance without interruption to customer details and deadlines.”

This means that it is imperative to have a program that includes tools that can handle poor-quality data and repair the data in a variety of formats. Delays in production often are caused by files that are incomplete, inaccurate, or have ambiguous design data.

Today’s software packages must have the versatility to read, interpret, and fix CAD data efficiently to eliminate this waste, said Dickin.

Shop Floor Programming

Not all programming needs to be done in a designated offline environment, however. According to Dickin, Delcam has long been an advocate of shop floor programming.

“Simply tweaking a program at the machine does give many benefits, however, the shop floor worker must know how to program in order to tweak, without doing more harm than good,” said Dickin.

Using software that allows programming at the machine as well as in a programming department results in an even distribution of the work load between the design department and the shop floor. Shop floor workers also tend to have a better knowledge of the latest advances in cutting tools and methods and know more about the characteristics of the different machines in the shop, so they can program them more efficiently.

The programmers on the shop floor may know more about the availability of items needed for the job, such as clamps and cutting tools, and can then program a part using what is actually available. They also should be able to adapt a program quickly if circumstances change, and respond faster if a program is not operating as efficiently as possible.

The programmers on the shop floor also can examine the cutting process closely as it proceeds to ensure that it runs smoothly, efficiently, and without error.

Scrap Reduction

“Today’s software includes sophisticated gouge-prevention and collision-detection features that prevent damage to the workpiece,” said Dickin. “This reduces the chance of any error that could scrap the part. As parts and machine tools become more sophisticated, accurate simulation has become more and more important. It is much cheaper to check a program on a computer than on an expensive machine tool.”

Programming software also allows accurate time calculations that can be used to quote a job. This can help shops avoid overquoting, which might mean losing the project, or underquoting, which might mean having to run the job at a loss.

For more information, visit www.delcam.com.