It is interesting to see how the machine tool market has evolved in the last few decades. When I started buying CNC mills in the mid 1990s there were more builders in the market and the price disparity between commodity machines and high-end machines was much smaller. There were more mid-range machines available that offered a good balance of price, performance and tech features.

Small shops were being forced to adopt CNC milling to remain competitive. Adopting CNC milling technology allowed small shops to automate the milling process in the same way and for the same reasons that large manufacturers had adopted it. Not surprisingly, many small shops gravitated toward the commodity milling machines because they provided an economical way to automate their machining and stay competitive.

At that time the goal was to have a machine that could perform repetitive motions, create multiple pieces of geometry in one hold and allow the skilled machinist to monitor and adjust rather than turn handles. Commodity machines provided the vehicles for this transformation.

A new day

The landscape is different today. In the past, I was a proponent of small shops purchasing commodity machines, and I even wrote articles discussing how a small shop could be efficient with them. Unfortunately, it is difficult to see how most small shops can continue to be successful with commodity mills.

Process capability, or more accurately, the need for process capability is going to drive shops to move away from commodity machines.

Six sigma is the name given to the science and mathematics of process capability that everyone has heard about. While the tools can be complex, the goal is simple: Create machining processes that are accurate, precise and reliable so that the finished product is made to the desired specifications with as little intervention as possible.

Small shops were never under the same pressures that necessitated process capability for large manufacturers and, therefore, it was of little concern. Again, things are different today. While small shops will not need to employ the complex statistical tools associated with six sigma, they will need to adopt the concepts to be successful in the future

Those entering the workforce today rely unconditionally on digital technology, in every part of life. Although it seems there is a robust DIY community out there, few DIYers are familiar with the tactile nature of making things. Skilled machinists in the past were accustomed to the feel of a machine’s handles, and relied on their senses to understand what was happening with their machines and cutting tools. Digital technology is quickly eliminating the tactile experience from machining so younger machinists are not as adept at interpreting machine performance by sight, sound and smell.

Sight, sound and feel

In the past, when a new machining process was introduced, it was expected that the machinist and engineers would fine-tune it by speeding it up, slowing it down or changing to a different tool. Newer machinists may not have the opportunity to learn by sight, sound and feel like their predecessors, so machining centers and machining processes must be more stable and accurate out-of-the-box.

Not only are younger machinists going to enter the workforce with a different set of experiences, there will be fewer of them. More and more, the expectation will be that one person monitors multiple machines. Their responsibilities will shift from piloting the process with constant inputs to monitoring machines and process conditions. Measuring parts, changing tools, loading stock and making setups on multiple machines is quickly becoming the standard for machinists. Machining centers must be capable of producing parts to the specifications repeatably without intervention to maintain profitable productivity levels.

Go to any trade show these days and you will see a plethora of automation like robots, gantry loaders and bar loaders. Machine tool builders have recognized that shops of all sizes are turning to automation to resolve labor issues. Automation is costly, and the only way to get an acceptable return on the investment is to have it work flawlessly. To do this, the machine tools must be highly repeatable. If machinists are required to continually interact with the machining processes, then the true value of automation will not be realized. Accurate and repeatable machines are a necessary foundation for successful automation projects.

Machine tool market

So how does the need for process capability impact the machine tool market? Commodity machines are not able to perform at the same level as the “high-end” machines.

First, the commodity machining centers are constructed differently. Manufacturers utilize lower cost construction techniques like fabricated steel weldments. While these techniques deliver good serviceable machine tools, the machines are less stable than those constructed using more traditional methods like casting.

Commodity machines typically rely on lower cost linear and roller guideway systems. Though some of these are made with roller type guideways, when combined with less robust construction methods the resulting machining center becomes more susceptible to the various forces acting on it, making machining processes less stable.

The more robust and advanced machines also come with features like thermal compensation, which measures the position of critical components that change when the machine heats up and cools down. As the machine moves from thermal forces the control compensates for the movement and works to eliminate the need for tool and work offset adjustments — all of which makes the machining processes more stable.

Changes in the workforce will continue to drive shops toward automation. Shops are expecting their machinists to manage multiple machining processes. Newer machinists and programmers are children of the digital age and expect little deviation between a simulated process and an actual process. For these reasons machining centers must be extremely stable and accurate.

What to expect

It is becoming increasingly difficult for shops to make money with commodity machines. Iin the future, small shops are going to move away from commodity machining centers in the same way we moved away from manual machines just a few decades ago. Shops will be driven to purchase machining centers that provide the necessary build quality and features that allow the creation of stable machining processes to address the changing workforce.