Machine/Control Simulation Means Better Results, Every Time

Ways of the Future, Here Now: As more shops seek to maximize their machining uptime, they are discovering that the ability to simulate actual cutting conditions offline has many competitive advantages.

In recent columns we’ve covered a number of machine tool control techniques related to maximizing your shop uptime. I want to explore a few more ideas that can increase uptime because no other topic is as necessary for a shop to tackle in order to remain competitive.

Uptime and machine utilization in any shop, big or small, are determined by numerous factors, including run duration, burden rate, material cost, part size and others. Nothing, however, is as critical as a shop’s ability to finish that first part as quickly and as accurately as possible, then let the onboard control manage the cycle. How the first part of each job is handled dictates the need for prove out and first-article machine trails. This is why the effective processing of that first part is so important to increasing shop capacity and reducing overall manufacturing costs on the floor.

Regardless of shop size, you can have a scenario in which the operator is running a part while simultaneously setting up the next job, then transferring the program to the machine control, whether via Ethernet, USB stick or even the wireless technology that’s fast becoming available to many shops. In fact, a number of the votech schools now routinely have their CAD students upload programs via wireless. That “way of the future” is here today. Check it out for yourself.

Something else that’s been viewed as an “emerging” technology is machine/control simulation software. Today control-identical and very advanced machine brand simulation software is on the market to assist programmers and operators alike in literally cutting the part offline by factoring in all the machine variables, clearances and tool paths, then hitting “cycle start” and beginning to visualize the sequence of events. This integrated approach computes accurate machining times for each operation and for the entire machining sequence by considering a complete model of the actual machine that accounts for its performance and response.

Because the actual machine kinematics are built into the program, approximations are few and a highly reliable simulation is achievable. Milling, turning and mill/turn operations are possible with many of the programs on the market today. Most of them will function on any Windows XP PC. And virtually every machine tool type can be stored in the library, including EDM, laser, waterjet, ultrasonic and more, since all the movement calculations are based on theoretical axes.

Accurate machine simulation is critically important with multi-axis machining because small changes in tool orientation could lead to significant rotary movement of the cutting tool, which in turn increases the risk of collisions or surface marking of the finished part.

By checking each NC block prior to execution on the machine, simulation can help you increase your material yield, improve your material costs and reduce your overhead expenses by detecting and stopping expensive gouges or collisions before they happen. The technology can examine and virtually verify the toolpaths that have been programmed and highlight segments where they might be optimized or improved, such as detecting unwanted axis reversals or excessive tool loads.

These fine details accumulate and expand into a larger scale as the simulation software provides your shop with the ability to compare jobs on different machines and even different technologies to achieve the optimum work schedule. Machine A might run a part in 22 minutes, while Machine B does it in 18 minutes, thus tightening up the quote process for any shop.

This means your planning becomes more thorough than ever before as even the smallest tweaks, such as rapids, can be accommodated by the software as it reads the feasibility of the cutter path and spots bad calculations at the front end. Think about what that means to your throughput. On average a program can be proved out in two-three hours using simulation software, versus 20 hours on the shop floor. That makes the best argument I can imagine for immediately investigating this technology for your operation.

That’s not all. Imagine being able to properly adjust your overall manufacturing plan, schedule tasks and account for resource utilization and its associated cost – all without having to add more staff overhead.

Last, but certainly not least, we come back to those material costs: your scrap rate will decrease dramatically. Just as important, your operators will find that their learning curve on a machine or program is much shorter, because most of the software screens simulate the actual control on the particular machine.