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Machining with the Environment in Mind


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May 14, 2009
It’s safe to assume that most shops recognize the importance of being environmentally responsible. However, benchmarking data suggests that the effort shops put into both recycling and reducing energy consumption varies.

Article From: Modern Machine Shop, Derek Korn, Senior Editor


Do shops feel that becoming more environmentally responsible is beneficial to their business as well as the planet? To find out, a portion of our 2011 Top Shops benchmarking survey was devoted to learning more about shops’ environmental attitudes as well as practices they’ve put in place to recycle and conserve energy.

Table 1, which was generated from the survey data, suggests the extent to which shops feel that implementing environmental programs is a helpful strategy. Approximately 43 percent of the Top Shops benchmark group (those shops that ranked in the top 20 percent of all survey participants based on key business and technology metrics) responded that environmental responsibility is either important or highly important to the success of their business. For the rest of the surveyed shops, this value was just 33 percent. Of all the shops surveyed, nearly 14 percent reported that a push to become more environmentally responsible is not a key component to the success of their business. Some of those shops cited added cost as a reason not to integrate technologies or practices to be more environmentally responsible. As evidenced below, however, many of the Top Shops say the benefits they’ve realized after taking such actions ultimately outweighed upfront costs.

Not surprisingly, the survey data indicates that the Top Shops (especially the large ones with gross sales topping $1 million in 2010) tend to be more proactive about identifying ways to reduce the amount of energy they use to manufacture parts. During the past year, the Top Shops have reduced the amount of energy consumed per unit of product output by an average of 5.1 percent. Because two survey participants reported unusually high percentage reductions for this question, however, the median value for this data sample, 2 percent, might be a more realistic representation of consumption reduction. (The median is not distorted by a couple of extremely high or low values in a given sample; it is the sample’s true mid point.)

While a 2-percent reduction might not seem terribly impressive, it shows that a number of the Top Shops are making strides to reduce overall energy consumption. Conversely, the median value for the rest of the surveyed shops was 0 percent for this question, suggesting that those shops either do not see value in curbing energy consumption or aren’t proactively taking steps to do so.

As noted in Table 2, virtually all of the Top Shops actively recycle, and more than half have energy management programs in place. That said, it’s interesting to see that compared to the rest of the surveyed shops, the Top Shops are less likely to have a formal, corporate environmental program. The same is true in terms of establishing carbon footprint values and integrating renewable energy sources such as wind and solar power (although just a very small percentage of shops seem to be looking closely at these measures.)

Perhaps the most telling feedback related to this topic is found at the bottom of Table 2. Approximately 5 percent of the Top Shops report they do not perform any of the environmental measures listed in the table. What’s more discouraging is that 23 percent of the rest of the surveyed shops don’t either. All of those shops are clearly missing out on opportunities to recoup manufacturing costs—via recycling, for example—not to mention opportunities to reduce their environmental impact.

The final survey question related to this topic was open-ended. It asked shops to briefly cite a specific environmental initiative from which they’ve benefitted the most. What follows is a summary of those responses. While this in no way is a comprehensive guide to becoming a more environmentally responsible machine shop, it does indicate where leading shops are focusing their efforts.

Recycling programs—Most respondents to the open-ended question cited the importance of recycling. In addition to being conscientious from an environmental perspective, recycling can also bring in money. Many surveyed shops recycle the chips created during machining. Some even integrate equipment to maximize the return on their recycling efforts, which can range from briquetters to centralized, facility-wide systems for chip handling and processing.

Fewer shops reported that they recycle used cutting tools, however, which is unfortunate. Shops can realize a good return, especially when selling back used carbide inserts and solid carbide tools. Many cutting tool suppliers offer carbide recycling programs that make it easy to sell back spent tools. With carbide scrap ranging from $11 to $13 per pound, it makes sense to have such a formal recycling program in place to recover this valuable material, notes Jeff Solomon, owner of Globe Metal Recycling Services Inc. Mr. Solomon says a good carbide recycling program begins with effective inventory control of both new and used tooling. One reason a formal program is important is to prevent theft. Because carbide is small and dense, employees can easily pocket a few pounds of it and walk out the door. Effectively tracking tooling assigned to each employee and securely storing both new and used tools helps prevent this from happening.

Mr. Solomon notes that there’s also value in recycling high speed steel tools. Some scrap dealers are not familiar with the tool steel grades and may pay just $0.15 or so per pound for it, as they would for regular steel scrap. However, scrap tool steel is currently worth more than $1.25 per pound, so it makes sense to separate and collect those tools as part of a shop’s recycling program in addition to carbide.

Coolant management—When coolant is properly maintained, its effective life can be indefinite and disposal costs can be eliminated. Some of the surveyed shops have such coolant management procedures in place. Other advantages to maintaining coolant versus disposal/replacement include reducing the amount of coolant concentrate to be purchased, achieving longer cutting tool life, improving part quality and minimizing machine downtime. Some coolant management companies even offer a mobile service in which they come directly to a shop’s location to recycle spent coolants or cutting oils.

A few surveyed shops have also switched to biodegradable, vegetable-based cutting oils. These oils provide an added level of safety because of their very high flash point, and their low mist formation means less product is consumed compared to similar mineral oils.

Minimum quantity lubrication—Approximately 10 percent of all surveyed shops perform some machining using minimum quantity lubrication (MQL). MQL delivers a very small amount of coolant to a cutter’s edge in the form of an oil mist or aerosol, as opposed to traditional techniques of flooding the workpiece and tool with a substantial volume of liquid coolant. It permits dramatic cuts in coolant costs, while protecting workers and the environment. And for the right applications, it can deliver improved tool life and surface finish for machined components.

More efficient machines—Simply put, modern machine tools are more energy efficient than their predecessors. In fact, one surveyed shop noted that the total amount of power it consumed at its facility decreased each time it replaced an old machine with a newer, more efficient model.

Machine tool builders continue to integrate design elements to minimize energy consumption. Some models stop the spindle motor, servo motors and fans inside the control panel during standby. In addition, more efficient LED lighting is increasingly common. Improved efficiency is being built into elements such as guideways, hydraulics and drive systems, too. In fact, some drive systems offer power source regeneration capability that transforms kinetic energy from decelerating servo and spindle motors into electrical power. Real-time monitoring of energy usage is also becoming more popular as managers seek to identify the prime drivers of energy costs during machining operations.

Right-sized machines—Lean operations focus on eliminating waste. As some surveyed shops noted, one way to do this is to purchase machines that are properly sized for the types of parts the shop will produce. Right-sizing equipment makes maximum use of floor space and consumes less energy than equipment that’s too big for the application.

Facility considerations—HVAC systems can represent a significant portion of facility operational costs. While some surveyed shops have changed to more efficient, controllable systems, others have benefited by a simpler change: raising or lowering (depending on the season) the thermostat temperature slightly during operating hours and more so during off-hours to reduce electricity used for heating and cooling.

Similar steps can be taken for lighting systems. Surveyed shops noted that savings can be realized by simply turning off lights when an area is not in use or by using timers or motion detecting devices. Other surveyed shops have completely revamped their lighting system. Old fluorescent systems that use T12 lamps can be upgraded by using the existing fixtures and replacing the T12 lamps and magnetic ballasts with T8 lamps and electronic ballasts. In addition, some surveyed shops have found that high-intensity fluorescent lighting is more efficient than the conventional metal halide systems they replaced.

Compressed air—A number of surveyed shops examined their compressed air systems and optimized them for reduced energy consumption and operational costs (the sidebar on the previous page lists tips for doing that). Also, control technology for new compressed air systems has improved to enable compressors to draw power only when needed. One surveyed shop says state energy credits allowed it to upgrade its HVAC and air compressor systems and realize a three-year investment payback.

Four-day work week—Something as basic as changing from a five-day work week to a four day week with 10-hour days can be beneficial. Since doing that in late 2009, one surveyed shop has experienced close to a 2 percent increase in productivity as well as a 5 percent reduction in energy costs.


Ten Compressed-Air Energy Saving Tips
Losses can make compressed air supply systems use more energy than necessary. Here are ten tips from Kaeser Compressors that can help reduce the amount of energy used by these systems:

1. Turn off your air compressors when not needed. A 100-hp compressor can cost $75,000 per year in energy costs (based on 8,760 hours at $0.10 per kilowatt hour).

2. Identify and fix air leaks. Studies show that 25 to 50 percent of all compressed air generated is wasted to leaks.

3. Eliminate inappropriate uses of compressed air. Using compressed air for blow-off is not only wasteful, it can be dangerous as well. In fact, using more than 30 psi for part and fixture blow-off is an OSHA violation.

4. Apply proper controls to multiple-compressor systems. Master system controls maintain a stable system pressure. They also ensure that only the needed compressor units are brought online and that they are operating at peak efficiency.

5. Ensure that piping and storage are adequately sized. Many systems lack adequate storage. (Kaeser recommends having both “wet” and “dry” tanks.) Also, undersized piping will increase pressure drop in the system.

6. Change filters routinely to eliminate pressure drop. Every 2 psi in pressure drop reduces compressor horsepower efficiency by 1 percent.

7. Consider automatic, zero-loss condensate drains. Capacitance-sensor-operated drain traps don’t need to be monitored. Plus, they discharge only condensate, not valuable compressed air.

8. Apply variable speed drive compressors where appropriate. Variable speed drive is not a one-size-fits-all solution. However, if demand varies, it can save thousands of dollars in electricity costs each year.

9. Reduce operating pressure to the lowest possible setting. Every 2-psi reduction in system operating pressure saves 1 percent in compressor efficiency.

10. Recover waste heat from coolers. A 50-horsepower compressor rejects heat at approximately 126,000 BTUs per hour. How might that heat be used?

Bonus tip: Finding incentives. Are you aware of the incentives local utilities offer for improving a facility’s performance with more efficient compressed air equipment? The Utility Rebate Finder at kaeser.com/rebates can help identify programs offered in your area.



Do shops feel that becoming more environmentally responsible is beneficial to their business as well as the planet?


Table 1: How important is environmental responsibility to the success of your business?


Table 2: Which of these environmental programs/practices occur at your shop?


Shops that throw scrap chips and remnants in the garbage instead of recycling them...


are throwing away money.


Because carbide scrap currently can yield as much as $13 per pound, it makes sense to have a formal recycling program in place to recover spent tools made of this valuable material.


VTD Systems, a shop profiled in a previous issue, upgraded its lighting system as shown here for increased energy efficiency and to provide a better work environment. Robert Vilagi Jr., the company’s president, replaced his shop’s existing bulbs and magnetic ballasts with a 320-watt, high-intensity-discharge metal halide system with electrical ballasts. This system is noticeably brighter and is said to save approximately 30 percent on energy costs.


Ten percent of surveyed shops perform some machining using minimum quantity lubrication (MQL), which delivers a fine oil mist to the cutter. MMS Online offers a variety of MQL-related articles in addition to an instructional video from our video contributor Todd Schuett (who provided this photo). The video explains how a shop might get started with the near-dry machining technique. Find these resources at short.mmsonline.com/mql


Article with Video From: Modern Machine Shop, Derek Korn, Senior Editor

MMSOnline Blog

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This article is reprinted with permission from Modern Machine Shop Magazine, and is protected under U.S. and international copyright laws. Modern Machine Shop Magazine is protected under U.S. and international copyright laws. Before reproducing anything from this Web site, call Gardner Business Media, Inc. (513) 527-8800.
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