Machinedesign 2043 Integrated Actuators 1101 0 0

Cost savings

Nov. 1, 2001
If only pricing motion systems were as simple as a stock boy gunning price tags onto cans of chopped ham

If only pricing motion systems were as simple as a stock boy gunning price tags onto cans of chopped ham.

Between factoring in value-added supplier services, time-to-market factors, operation costs, and maintenance expenses, the total cost of motion system ownership is often a large, elusive number. While acquisition costs may come to mind, the bills don’t stop there. Motors, for example, can use 40 to 60 times their initial purchase price in electricity over a ten-year life span.

Fortunately, hidden expense traps are avoidable and cost estimation tools can help you make wise purchasing and procurement decisions.

A systematic approach

Keeping costs down begins with smart shopping. For example, on industry average, buying an integrated system offers a 25% savings over buying separate components, according to Bayside Motion Group, Port Washington, N.Y.

“Typically, a large part of the cost of a motion system is the integration of the various components, that includes the cost of specifying and procuring each, as well as engineering costs,” says Avi Telyas, CEO, Bayside Motion. Ideally, the level of modularity should be such that the motion subsystem can be dealt with as one interaction, one training curve, and one commercial relationship as opposed to many.

Bayside Motion helps alleviate costs by taking motor, gear, and slide technology and putting it “under one roof.” For example, Bayside’s Stealth gearmotor combines a gear and motor, and its linear positioning stages have embedded motor drives. Having one component instead of two provides a more reliable system because there are fewer parts, as couplings, bearings, screws, and wiring are reduced or eliminated, says Telyas.

Integrated components are designed with better line-ups and typically run cooler than separate combinations. A system that runs cooler, of course, lasts longer. Integrated systems also are up and running more quickly, which allows more room to explore settling times, servo stiffness, response times, and other dynamic factors.

One question people often have about integrated systems concerns repair. In order to repair the motor, the whole system must be removed. Telyas says, “The truth of the matter is if you’re down, you’re down.” It’s the same level of difficulty to swap out an integrated system as a single component.

Animatics Corp., Santa Clara, Calif., is another component manufacturer offering integrated packages. With its SmartMotor, a motor, encoder, amplifier, and controller all built into one unit, system acquisition cost goes down, and maintenance costs are significantly reduced. Once the SmartMotor is in the field, a spare system can be stored and quickly swapped out, unlike a conventional system with a motor, cables, cabinets, and a controller.

Even higher levels of integration may be on the way. Bayside’s next step, says Telyas, is to include some of the drive electronics inside the positioning system or gearmotor itself. Bayside is waiting for the necessary miniaturization of electronics, but expects that to happen within the year.

Downsize downtime

While the component purchase price is important, the real cost of a product is the cost of failure, says Telyas. “Number one: never skimp on reliability,” he advises.

Welker Bearing Co., Troy, Mich., which specializes in PTFE self-lubricating bearing material products for such inhumane environments as welding lines in automotive plants and foundries, provides maintenancefree products designed to last the life of the program – and not cause downtime. Their components, including shot pins, slides, and lifts, come with a three-year warranty. While Welker’s shot pins are by far the most expensive on the market, they are standard at some DaimlerChrysler and General Motors Corp. facilities, says Thomas, because of their longevity. On an automotive assembly line that produces one to four cars a minute, the cost of downtime is far greater than the shot pin price tag; especially considering that the “buffer” of auto parts, conveyors of doors, and hoods, etc., must be re-stocked before starting the line again.

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Motor mistakes

Any time a machine or component must be replaced quickly there’s bound to be indecision. However, motors must be carefully selected because the difference of going from a motor that’s 92.6% efficient to one that is 94.3% efficient, for example, can translate to thousands of dollars worth of electricity over the motor’s life. While some are aware that the electricity cost savings gained with such premium efficiency motors quickly outweigh their initial purchase price, not everyone is jumping to buy them, possibly because efficient options are limited when making panic decisions during downtime.

Typically when a critical motor fails, facilities immediately contact a repair shop, and ask for a fix ASAP. With a rush repair, you could end up paying 60% of what it would cost to buy a premium efficient motor in some cases, says Neal Elliott, senior associate for the American Council for an Energy Efficient Economy. If it’s an extremely urgent job, you could end up paying 100% overtime and maybe up to 80% of the cost of a new efficient motor. On top of the high cost, Elliott says you cannot do a quality repair in a very short period of time. When a motor owner puts a repair team under the gun to do a quick fix, it’s a bit awkward to tell their customer “that they’re being stupid,” says Elliott. So, the shops do the best job they can in the given time frame, even when it’s not in the best interest of the customer. The result may be a motor that is neither reliable, efficient, nor cost effective.

Elliott explains that the engineering team without a motor replacement plan often has a blanket purchase order for motor repair, but can’t buy a new motor because it requires a capital purchase authorization. So, even though they know it’s clearly not a cost-effective solution, they send the motor out for repair.

Motors in general are very reliable, long-lived components that often fade out of thought, at least until one fails. Despite their generally benign existence, electric motors constitute 64% of industrial demand for electricity. Bringing this figure down is the goal of the Consortium for Energy Efficiency motor efficiency awareness campaign “Motor Decisions Matter” offering advice on how to implement a plan to switch to energy and cost-efficient electrical motors. The campaign offers strategy tips and links to more information at

As far as making decisions when a motor breaks, Elliott says, “We want to move it from a panic phase of running in circles screaming and shouting to planning a solution. Because when you do that planning, you can end up with a more efficient and, in many cases, less expensive product.”

Decisions, decisions

While there are several means of powering a full motion system, pushes in certain areas are evident. Tim Thomas, application engineer and designer for Welker Bearing says some schools of thought, influenced by Europe, are calling for an all electric automotive assembly line.

“The electric market is one that’s up and coming, but it’s not nearly realized,” says Thomas. Hypothetically, hydraulic oil may cost $200 a drum, but could cost $1,500 for disposal in the U.S., Thomas says. However, hydraulics are popular in second-world countries such as Mexico and Brazil, particularly where it is extremely hot. It’s difficult to get clean air for pneumatics, and compressed air lines are plagued with condensation and rust problems, he explains. Others are looking to electromechanical devices as a cost-saving replacement for traditional fluid power systems. John Walker, national sales manager at Exlar Corp., Minneapolis, says of integrated electronic actuators, “A lot of interest is due to the fact that a typical hydraulic system is maybe 40% efficient, whereas electromechanical systems with high-efficiency screw mechanisms are usually closer to 80% or above, meaning that for the same amount of work you’re using half the electrical energy.”

Cost savings through energy conservation are not limited to linear actuators. Motors purchased as part of a fan or pump can be strategically selected to save money. CEE recommends explicitly specifying premium efficiency motors in these devices when soliciting bids because they may not be included automatically.

Another system-level decision is whether to go with direct-drive servos or a gearhead reducer. Some say gears are on the way out, but a tutorial from Neugart USA LP, Bethel Park, Pa., making the case for planetary gears as a more costeffective option in servo applications states, “A torque increase goes hand-in-hand with a cost increase. Besides more expensive magnets comes the need for stronger mechanics and a larger, costlier controller. The controller and power electronics have to be able to handle the higher currents, which increase proportionally to the torque. In most cases it is less expensive to boost the torque by a gear reduction.”

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What’s more, gearheads are getting easier to integrate. Chicago-based GAM, for instance, offers planetary gearboxes that connect directly to a linear belt-module or ballscrew. There is no need to purchase a separate coupling from a different manufacturer or build an adapter housing.

Sometimes a designer does not need top performance products and doesn’t want to pay for unnecessary features. Many component manufacturers respond to this market niche with an “economy” version. Bayside’s Telyas warns, though, to beware when bargain hunting and make sure the component still contains a bulk of the technology for which the company is known. Bayside, for instance, is able to provide low-end Stealth model gears maintaining a 70% component overlap with the high-end model. They sell for almost half the cost of the highend line because they are sold in large volume. Groschopp, Sioux Center, Iowa, also offers an economy class gearhead.

Distribute the cost

Relying on distributors and suppliers to provide cost-saving service is gaining popularity, and distributors are responding by offering new venues of savings.

Rick Savela, national industry manager-OEM, Applied Industrial Technologies, Cleveland, states, “Because many small and mediumsized OEMs don’t purchase enough components from the original maker to qualify for a significant price break, they are capturing cost-efficiencies and other added values from their distributor.”

However, direct supplier-to-OEM distribution via Internet sales may offer a price break opportunity for smaller firms. The online marketplace, for example, offers direct e-sales of electrical distribution, automation, and control products. The dot-com owned by Elestream SpA and SIEI SpA of Italy will carry SIEI brand products including ac drives, motor starters, and switches. Because the product will be sold direct online, not through distributors, small and mediumsized customers will get volume level pricing, says Christopher Bradley, VP of U.S. operations for Elestream in Charlotte, N.C.

Unusual supplier partnership approaches are cropping up where competitors drop the swords and pool their resources and know-how to efficiently produce better, more cost-effective designs. Many were surprised when Toyota Motor Corp. and General Motors joined R&D forces in an effort to accelerate market introduction of automotive fuel cells. Now two of Toyota’s bearing suppliers are doing the same with direct distribution and services. The Timken Co., Canton, Ohio, and NSK Ltd., Japan, have both served Toyota independently but are now working cooperatively to provide innovative bearing solutions faster, says James W. Griffith, president and COO, Timken. The result is reduced overall costs for Toyota via teams of marketing and engineering reps from both NSK and Timken. The application engineering, order fulfillment, and manufacturing arms of both companies support the hybrid teams.

CAD shortcuts save R&D dollars

In any economy, analyzing and maximizing process efficiency is one way to make a buck. Shortening the design cycle is another. Avoiding unnecessary CAD modeling and redrawing saves hours and money early in the R&D phase. The value of using CAD part libraries to do just that is substantial. The “Thomas Register CAD Economic Impact Study” reveals that a total of 10.1 million parts are inserted into designs from CAD part libraries and other sources each year. Five million of those come from the Thomas Register of American Manufacturers Part- Spec and PlantSpec CDs, two libraries of manufacturer’s catalogs including downloadable CAD drawings and technical product information. According to the study, companies reportedly save 317 hours a year by inserting Thomas CAD model parts into their designs and the individual engineer saves 84 hours a year, with a dollar value of $9,791 annually.

The lack of interoperability between CAD systems has been an expensive problem since the second CAD system was introduced. The National Institute of Standards and Technology estimates that CAD difficulties cost the U.S. automotive industry alone more than $1 billion a year.

Traditional translation methods include using file formats such as STEP and IGES and manually recreating models in the target CAD system. These approaches have their shortcomings. Neutral file formats have the ability to translate models into a target system, but the valuable individual feature information designed into the source CAD model is lost. This method creates a dumb solid that cannot be modified in the target system. The second approach, manually recreating the files, can include feature information in the target system. But this process is time-consuming, subject to human error, and expensive. Costs include engineering time, the purchase of CAD seats in both the source and the target systems, and the potential cost of errors in the recreated model not being detected until after the product has reached the manufacturing stage.

Now, for the first time, fully native feature-based translation is available between SDRC I-DEAS, PTC’s Pro/Engineer, Dassault’s CATIA, and USG’s Unigraphics via the Acc-u- Trans Interoperability Engine from Translation Technologies Inc. (TTI), Spokane, Wash.

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Full translation has been a long time coming because while CAD programs can often perform similar tasks, the way they get from A to B is often different. To simplify, one CAD system may say “2+2=4” while another system may arrive at the same result by saying “1+1+1+1 =4” because the number “2” is not efficiently employed by that system. Such discrepancies on a more problematic mathematical level explain the complexity behind creating a truly native translation, according to TTI.

By cutting translation rework with TTI’s Acc-u-Trans service, some companies including Sikorsky Aircraft Corp. and Goodrich Sensor Systems have saved up to 50% of the cost associated with remodeling parts and reduced the design cycle time for translated parts by as much as 75%.

A look at the electric bill

At most facilities, electricity metering takes place at the service entrance. Beyond that point, many system engineers don’t know much about what they’re paying for electricity. Part of the problem, says CEE’s Elliott, is that industrial electric rates are not like home consumer rates.

An industrial bill consists of an energy and a demand portion. Most larger facilities have a variable time-of-use pricing on energy use and a declining block structure on rates. For example, with the first 1,000 kWh, you pay one rate, then for the next 1,500 kWh you pay a lower rate, explains Elliott.

The demand charge is based on a day or night rate reflecting the maximum rate of power consumption. This charge is justified by the electric utility’s provision and maintenance of substations and power lines capable of handling the peak electrical current required. Power factor and other charges have similar reasons behind them, hence frequent confusion. CEE advises checking with your provider to see if you are using a rate that reflects your true cost of power.

To help estimate the overall impact of energy-saving measures, you can calculate your aggregate cost of power by dividing the grand total cost of electricity by the number of kilowatt hours consumed in a standard billing period.

Lifetime costs add up

Total Cost of Ownership (TCO) Toolbox software from Rockwell Automation, Greenville, S.C, helps consultants identify areas where cradle to grave system ownership costs can be lowered, probing into maintenance costs, operating costs, efficiency, equipment life, and production output. The basic methodology is review of the full process, detailing the activities that impact the problem and finding the best possible solution. During initial testing, Rockwell Automation identified $1.4 million in savings at more than 30 customer locations.

A consultant uses the software to analyze the process data and generate flow charts showing the relationships between each step. Bar charts and full data sheets are also available. While outlining the process, customers are allowed to quantify steps in their own terms, getting as specific as “bagels per minute output.” All values are assigned, so the software can be used to quantify the cost of ownership for Rockwell Automation products or existing systems.

Comparisons can be made on a product or system level because it is activity based. For instance, the activity of combining components in a system can be documented just as the activity of not having to lubricate a bearing, explains Joe Razum, senior business analyst for Rockwell Automation. Rockwell Automation representatives believe this is the first software tool to combine activity-based costing and total cost of ownership analysis.

“(TCO) gets a lot of credibility from customers because it’s a neutral software and they are using their own data,” says Razum.

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