Dos And Don’ts Of Machine Tool Purchasing
In reality, the purchase price of the machine tool is small potatoes compared to the dollar volume of product a company plans to process through the machine. The machine’s price is insignificant compared to the labor costs for companies to operate older, less automatic machines or compared to the maintenance costs required to maintain aging machines in a shop.
For many customers, especially first-time buyers, purchasing a machine tool can be a frightening experience. A CNC machine tool, along with the many accessories and available options, can add up to some serious money. At Marubeni Citizen-Cincom, the average sale of one machine is $175,000. This all too often seems like an ominous price tag and sends customers into sticker shock. In reality, however, the purchase price of the machine tool is small potatoes compared to the dollar volume of product a company plans to process through the machine. The machine’s price is insignificant compared to the labor costs for companies to operate older, less automatic machines or compared to the maintenance costs required to maintain aging machines in a shop.
Unfortunately, people tend to buy machine tools in much the same way they buy cars or big-screen TVs. The only thing that matters is the price tag and of course, whether or not we want them in the first place. However, no one buys a machine tool because they want one or because they are the right color. They buy a machine tool because they have a product to make or a business to run. In short, it is bought to make money. Therefore, the first question should not be, “How much is this machine?” but rather, “How can this machine make me money?”
Obviously, the machine will make money if it can make your parts efficiently. Therefore, the first concern should be that the machine has the capacity, tooling and functions to make your parts. The easiest way to find out is to ask the machine tool builder or distributor to process your parts and come up with a cycle time estimate. You should provide representative drawings of the parts you make to several builders or distributors for evaluation. Also, be careful not to expect one machine to make all your parts. The logic that big machines can make small parts while small machines can’t make big parts is misleading. Big machines usually have slower spindle speeds that are necessary for small parts, but the bigger tooling and workholding devices may not be able to handle small parts efficiently.
Unless you are an R&D shop, efficiency (not necessarily cycle time) is the key. Efficiency in the machine tool is dependent on many factors. Given that metal removal rates are constant, the cycle time will be largely dependent on rapid traverse rates, tool change times and, most importantly, the ability of the machine to introduce several tools to the workpiece simultaneously. Today’s multi-axis machines take advantage of this multi-tool capability to drastically increase productivity. Look for machines with subspindles that can do front and backwork simultaneously or machines with multiple tool posts that can do simultaneous work on the main spindle. Marubeni Citizen-Cincom sells these features heavily, as the company manufactures machines capable of three or more tools cutting simultaneously.
Other factors of productivity or efficiency are found outside the machine in the form of automatic bar loaders and part unloading devices. These accessories, as well as others such as high-pressure coolant systems and monitoring systems, can drastically increase the efficiency of a plant, and reduce the number of operators required to run large banks of machines.
By far, the most important factor of productivity is reliability. The machine with the best cycle time can lose a lot of ground if it is down and not making parts. A machine that is down for any length of time can cost an operator efficiency. We believe that local service and support are keys to making a good machine tool great. Therefore, consider this factor when making a machine tool selection. Buying a reputable brand from a well-known builder and through a machine tool dealer that you trust is another key element to success. The sweetness of a better price from Brand X will sour quickly in the wake of downtime with little or no support and will cost significantly more in the long run.
The bottom line is getting parts out the door that can be sold at a profit. The price tag, including the machine accessories and tooling, should be considered in light of how efficiently it will make parts. Remember that looking only at the price tag can negatively affect downtime, labor costs, work-in-process, setup time and secondary operations. Efficiency, reliability and support from a builder or distributor will benefit your company in the long run.