In considering the purchase of items such as machines, tooling, inserts, or coolant, the most obvious piece of data is the purchase price. If you request quotes from a variety of vendors offering comparable products, it can be tempting to use those figures as an immediate basis of comparison. Unfortunately, purchase price fails to take into account the many ways in which the selection will ultimately affect your company's bottom line. Those who base their decision only on this solitary piece of information will fail to truly minimize their costs.
An investment should be analyzed based upon its total impact on operations, not just its initial cost. For instance, consider the purchase of a machining center. If a machine costs 5% more than a competitor's model, but increases throughput by 30%, it should easily justify the additional investment. Increases in productivity and efficiency will often more than compensate for a higher price tag.
Additionally, the quality of the products being compared should be considered. A cutting tool might look promising on paper, only to provide a quality of cut below the standards required by the part being machined. This could result in costly scrap or the shipping of sub-par product to a customer, and both outcomes are detrimental to profitability. Either of these will negatively impact your business and become detrimental to long-term profitability.
On an even more subtle level, you must consider the soft costs of a product. Where one machine might require a massive retraining program for all those who will be using it, another would only require a brief session. If a large number of operators are using a new machine or a new tooling system, you should take into consideration how easy or how complicated the addition will be to operate. Another soft cost involves repeatability and consistency. If a machine's output experiences variation depending upon which operator is using it, that inconsistency is damaging to profits. Additionally, if a tool demonstrates poor repeatability, more labor hours must be spent constantly verifying that its performance is meeting the required quality levels. This effort wastes employee resources, and can be prohibitive to incorporating high levels of automation that might benefit your company's operations.
Lastly, an investment must be analyzed on the basis of how it will affect other components being used. For instance, a machine in regular use will often require a spindle overhaul at some point, meaning downtime and increased costs. By using properly balanced tooling that is correctly chosen for the machine in question, spindle life can be significantly extended. In this case, the correct tooling allows you to realize the greatest possible return from the investment you made in the equipment.
On the flip side of that coin, improper tooling can cause a machine to perform well below its potential, obviously having a greater effect on total costs than the purchase price of the tooling. For instance, if your tooling can only tolerate a max of 10,000 rpm and you invested in a machine with a 20,000-rpm spindle, you will be paying for a benefit not received.
Today's technological innovations afford you a wider variety of solutions than ever before available. While this range of possibilities offers increased potential for success, it has also complicated the purchasing decision. If you wish to maximize your profitability, you have much to gain by examining all the options, and discovering the solution that truly minimizes costs and boosts the bottom line. Following such an approach will not only result in a more efficient operation, it will also improve your company's ability to compete in this ever-more-challenging global marketplace.
This article was first published in the August 2005 edition of Manufacturing Engineering magazine.