CAM software considerations

Mitsubishi Hitachi Power Systems Americas (MHPSA) is setting up a new facility in Texas to support the service operation of our business. The new shop is fully operational, but decisions are still being made on items such as tooling and CAM systems.

MHPSA uses several different CAM systems to program machine tools, which prompted the manufacturing manager in Texas to ask which system I recommend. When asked, most manufacturing engineers and programmers will simply spit out the name of their favorite software. If challenged, they can sometimes present an argument or two to substantiate the opinion. I, too, have favorites, based on proficiency and comfort more than anything else. However, my answer to the manager’s question was not the name of a software package. Instead, I challenged him to consider some elements that are often overlooked by machine shops when evaluating CAM software.

I do not feel that one of the major CAM packages has a functionality advantage over the others. Although each promotes some special tool or feature, they all perform similar functions and provide similar results. Nonetheless, there are some factors that should be considered when buying one.

First and foremost, the software must be suitable for the parts you manufacture most often. In other words, buy software for your “bread and butter” work, and avoid buying options and features for jobs you are not already manufacturing. If you find there are situations where the software tools are inadequate, you can always upgrade and add features later.

Sometimes when you think a software upgrade is necessary to overcome a difficult situation, you can find an alternative solution. Software developers typically offer tech support to overcome challenges. I thought my software was inadequate for several situations, but the tech guys showed me tricks to circumvent each problem.

Before you buy CAM software, bring in an expert to demonstrate it. Give the expert one of your parts and see if he has trouble programming it. If so, you will also have trouble. The ability of the software representative is also an indicator of the overall ability of the company to provide service and support.

Each CAM package uses a post-processor to generate code for the machine control, and different machine controls require a different post. Each software company handles posts differently. Some give them away, some sell them and provide editing, and some allow users to make changes. It is important to discuss posts before buying the software. A bad post will not output useable code, necessitating entry of manual edits and causing lots of aggravation.

Many shops believe CAM and CAD software are both necessary to operate CNC equipment. This is not the case. Depending on the complexity and volume of work, CAM software may not be a necessity.

If your shop is making parts that are not complex, it may be more productive to write CNC code at the machine. Parts that have simple contours, keyways and drilled and tapped holes can be programmed efficiently at the machine. Some will argue that programming at the machine interrupts production time. However, today’s controls often have a background editing feature that allows programming while a machine is operating.

Mitsubishi’s shop in Texas operates machines with a user-friendly interface—developed with the machinist in mind. This conversational control allows the user to quickly and easily program parts at the machine, selecting machining operations from a menu and providing the necessary information. After the information is entered, the control creates code and places it in the program body to build a part program.

When true conversational programming is not available, many canned routines are available in most G-code controls to speed code creation. Drilling and tapping cycles like G81 and G84 are included in all modern controls. Learning to utilize these can allow the machinist to create programs quicker than using CAM software.

Almost all of the control manufacturers include some type of internal conversational programming aid. Often shops are not aware of control features like conversational programming or background editing. Approach control manufacturers with your parts and ask them how they would create the programs without CAM. They should be able to show you numerous timesaving techniques.

That said, I am not opposed to CAM software. I suggested the above workarounds because software and training are expensive and often mean hiring another person. It’s important to understand that there are alternatives and not mistakenly react to a perceived need.

Software is a tool just like a vertical machining center or lathe. Performance and productivity are most often a function of the person using the tool and not the tool itself. CTE

About the Author: Christopher Tate is engineering manager, combustion shop, for Mitsubishi Hitachi Power Systems Americas, Savannah (Ga.) Machinery Works. Email: chris23tate@gmail.com.