What does sustainable machining mean today?

(created by Patrick De Vos )

When society attempts to simplify complex ideas – or perhaps obscure their true meaning – it attaches a blanket adjective to a particular subject. These “buzzwords” usually generate more questions than they answer. An excellent example is “sustainable,” now applied far and wide to subjects as diverse as fishing, farming and fashion. Even machining, with centuries-old origins, now wears the “sustainable” label, and what that means is neither simple nor clear. Sustainable can refer to economy of operation, ecologically responsible practices or ways of dealing with ethical or geopolitical issues.

For those in the machining industry, it is best to narrow the discussion of the components of sustainability to technical concerns – namely economy of operation, resource and energy efficiency and waste reduction. In general, sustainable machining enables a company to produce competitively priced products of a quality that is sufficient to meet the needs of its customers and deliver them on time. Thereby, the manufacturer can sustain itself as a viable business. 

Quality, repeatability and flexibility

The first goal of machining sustainability is achieving the required level of product quality. As batch sizes shrink under just-in-time production practices, each workpiece takes on greater value. When a part is rejected for insufficient quality, everything invested in producing it is wasted, including capital spending and the cost of energy, labor and raw materials. To halt the waste a shop must develop and master machining processes that eliminate scrapped parts.

The next focus is on unceasing repeatability. Achieving that level of discipline enables a shop to continually meet customer needs in a timely way.

After repeatability, flexibility is needed to handle variability in demand and accept it as an opportunity. An organization has an advantage if it can efficiently provide sufficient production flexibility to fulfill rapidly changing customer demands.

Efficiency

Keeping machine spindles running is a traditional measure of a shop’s efficiency. It should be noted, however, that stopped spindles do not necessarily result from a lack of workforce interest or effort. Idle machines may indicate that the facility’s organization overall is not optimized. Operators should have immediately on hand everything they need to produce a certain part. This includes not only tooling, fixtures and raw materials, but also the information to know exactly what they need to do and when they need to do it.

A worker without the proper equipment or information to carry out a job may have to stop the machine or leave it to obtain clarification on certain tolerances, gather missing fixturing or tools or seek advice about the machining procedure at hand. Machining processes in general are well controlled, and problems may not involve cutting speeds and feed rates. Effectiveness and efficiency will suffer, however, relative to the organization (or disorganization) of the overall production process.

For example, SECO performed a shop evaluation that included a labor productivity analysis as well as an Overall Equipment Efficiency (OEE) measurement. Labor productivity was nearly 100 percent, but the OEE measured only 20 percent. The employees were working as hard as they could, but that didn’t keep the spindles running. Much of their effort was consumed in gathering process elements that were not provided or unclear.

Pricing for sustainability

A key factor in the economic aspect of sustainable machining is determining pricing. The price set must cover the shop’s costs and profit but must also reflect what the customer is willing to pay for the value received. High-end prices are market driven and can only rise to a level above which potential customers will seek other sources for the products they need. Prices set too low will not enable a shop to cover its costs and margins.

In between those extremes is a window of sustainable prices that will enable a shop to sustain its future. When production costs are under control, the window is broad and it is possible to sell products at price that is appropriate for their value, recognizing that competition and economic conditions will reduce the maximum price a shop can charge. At the same time, higher energy and material costs and rising salaries will increase a shop’s production costs and raise the lowest prices it can set, narrowing the window of sustainable pricing.

Sustainable machining results from balancing the cost of fulfilling customer needs with pricing that enables a shop to fund its operations, pay its employees, make a profit and grow.

For more information about the sustainable machining production check out our latest blog article.