When and How to Add Machinery
Knowing when the time is right to add machining capacity is one of the toughest challenges shop owners face. Even one new machine is a considerable investment for all but the largest manufacturers, which means most shops won’t even consider a new machine until they have more work than they can handle with their current equipment. However, machining capacity rarely tells the entire story – and when manufacturers study their entire process, they often find that the sources of these capacity issues aren’t where they thought, particularly in high-mix/low-volume (HMLV) production environments.
In HMLV shops, manufacturers often discover bottlenecks in many unexpected places, and a careful investigation will show that they’re interrelated in most instances. In the front office, a sales professional eager to make a deal overpromises to the customer. The programmer, seeking an optimized process, selects a new set of tools and makes educated guesses about a part they’ve never seen before. The operator, given one chance to get this one-off part right, dials the suggested cutting conditions down by 50 percent. The end result is a suboptimal process with substantial setup and idle time – and in many cases, a broken promise to a now-disappointed customer. And at no point in this process would a new machine solve anything.
Despite this, a new machine often looks like a simple solution to a complex problem. When it seems as though job orders are coming in faster than finished parts are being shipped, additional machining capacity seems like an easy way to get those job orders filled. All too often, however, that easy solution becomes a big headache: new technology requires training, more capacity means more machines for operators to oversee, and more jobs necessitate more engineering and setup time. The only way to solve a complex problem is thoroughly understanding the challenges involved, and an effective way to approach this is through an Overall Equipment Effectiveness (OEE) evaluation.
An analytic tool that examines the entire manufacturing environment to arrive at a more robust understanding of capacity, OEE is the process of identifying total available production time and subtracting all non-productive time – from planned downtime and changeovers to minor stops and unscheduled breakdowns – to arrive at the effective machining time. Shops that pursue a high-volume production strategy will find this to be a much easier process than HMLV manufacturers, as a handful of extremely well-defined processes are easier to track than dozens of new jobs a week.
There are, of course, many solutions for HMLV challenges. Machine monitoring will make it much easier to spot these issues in the first place at the same time it would provide data for a more comprehensive understanding of OEE. After identifying these issues, one reliable way to approach solving them is standardization. Universal-style tooling, for instance, prevents unnecessary setup time. When operators approach every given type of part feature in a particular material the same way, they gain confidence in the programs and cutting data they receive from the front office.
After maximizing their OEE and minimizing downtime, manufacturers will have a much better understanding of their capacity, which, in turn, allows them to better make decisions about adding machinery. At this point, shop owners should carefully consider strategic factors involving the trends in their particular markets and relentlessly seek out a true competitive advantage. Shops can easily meet capacity, but profitability requires filling up that capacity with the right kinds of jobs, the ones that you can produce most effectively. With a complete understanding of what your capacity is, and what types of business you should be pursuing for the most sustainable growth, you’ll have a much better idea of what kinds of investments you can make to reach your goals – including, when necessary, a new machine.