Four Tips for Effective Component Selection

The selection of components for machines developed by startup companies as well as those by established brands impacts the machine’s cost, time to market, performance, maintenance and overall longevity. Here are four tips for optimal component selection:

Tip 1: Begin Machine Design by Adopting Industry Standards and Norms

Whether a machine is the first of its kind or a next generation version of an earlier unit, that machine will be slotted into an established environment of standards and norms for power, connectors, fittings, sizes, materials and safety.

Industry standards have been integral to machine design for 140 years in North America. The American Society of Mechanical Engineers (ASME) published its first industry standard in 1884. That standard covered steam boilers, one of the most important and dangerous devices of the steam age. The American National Standards Institute (ANSI) published its B11 standard for safety in 1922. B11 is considered the first machine safety standard. It is vital for the designer to know and follow the standards of the machine’s environment. Some of the most important standards for organizations today, including ASME and ANSI, are:

The American Welding Society (AWS)
The International Electrotechnical Commission (IEC)
The Institute of Electrical and Electronic Engineers (IEEE)
The International Society of Automation (ISA)
The International Organization for Standardization (ISO)
The Manufacturers Standardization Society (MSS)
The National Electrical Manufacturers Association (NEMA)
The National Fluid Power Association (NFPA)
Underwriters Laboratory (UL)

In addition to standards, there are also customary practices for machine design, including everything from the size and type of bolts and connectors to power requirements. Think of these practices as industry norms—but not standards. Designers should research the various aspects of the machine’s environment to ensure conformance to both standards and norms. Talking with suppliers is one of the best and most efficient ways the designer has to ensure adherence to standards and norms for the components in question.

For example, a company contacted Festo looking for a proportional pressure regulator. Before calling Festo, the company had developed a custom circuit board to communicate with a regulator. The circuit board was based on 0 to 5 volts. Festo could supply regulators for the industry norms of voltage, 0 to 10 and 4 to 20, but not 0 to 5 volts.

This machine builder had designed a circuit board suitable for only a few proportional pressure regulators, and those few were not optimal for several reasons. Instead of having the widest possible selection of pressure regulators from Festo and other suppliers to choose from by using normal voltage, this company had limited its choices, leading to higher cost and potential supply issues over the life of the machine.

Tip 2: Apply Standard Off-the-shelf and Well-supported Custom Components

Standard off-the-shelf components for the sake of this article are defined as components that meet national or international standards. Vendors’ custom components typically represent product lines that do not meet standards but are widely applied by machine builders. Knowing the difference is important because both types offer wide availability and reasonable choices.

Most of the leading component suppliers have a portion of their product lines designed to meet industry standards from the organizations listed above and others. Designers who strive to select components that meet a specific standard will find broad availability from multiple vendors of competitively priced drop-in-ready components. As the machine ages, components built to a standard have a good possibility of remaining available, which makes maintenance easier and prolongs the life of the machine.

The leading suppliers tend to innovate within the standard. In other words, while a product may meet the standard, it may also represent the latest advances in manufacturing and design. For example, Festo replaced its DNC ISO pneumatic cylinder with the DSBC ISO cylinder. The DSBC’s piston is about half the size of the DNC. Festo accomplished this reduction through a new manufacturing process. Festo used the freed-up space within the cylinder for improved bearings and cushions. The DSBC and DNC are interchangeable, but the newer cylinder features longevity and operational improvements.

Festo DSBC cylinders are interchangeable with other ISO 15552 components, but they now have new features offering prolonged longevity and enhanced operation.

For those vendor components not built to meet a national or international standard, identify suppliers that have a broad and well-stocked range of those parts. A good example of a custom product that customers can rely on is Fabco Air’s pancake compact air cylinder, which was first produced in 1958 and is still used today.

An extensive custom product range indicates the supplier considers these parts a specialty. The implication is that the supplier will keep these components, or equivalent components, available for an extended period.

A good example of a custom product is Fabco Air’s pancake compact air cylinder, which was first produced in 1958 and is still going strong, giving customers the assurance of availability.

Tip 3: Be Knowledgeable About the Cost of Customization

Sometimes it seems that only a customized component will do. Customization, however, implies higher cost. When asking a supplier to customize components, the designer will find the lower the volume, the higher the cost. Volume and cost are in an inverse relationship. As one variable rises, the other variable falls, and vice versa.

C = k/V + C_min

Where:

C is the cost per custom unit
k is a constant that determines the proportionality between cost and volume and is based on the actual cost structure
V is the sales volume
Cmin represents a minimum cost per unit that doesn’t drop below a certain threshold.

There are strategies the designer can use to lower the cost of a low volume customized component. Standard and custom components are designed to achieve the highest level of performance over their lifecycle. The startup machine or the next-generation machine may not require this level of robust performance.

There is nothing to say the machine designer cannot work with the supplier to simplify the design of a standard or custom product to detune performance down to the level required. For example, a cylinder may be designed to perform 10 million cycles. Perhaps the new or next generation machine requires only 1,000 cycles. It is possible a supplier will work with the designer to substitute less expensive parts for the lower cycle count.

The Festo Motion Control Package control panel for multi-axis handling systems is a configurable product. The Festo Customer Solutions Department in Mason, Ohio is regularly engaged to cost effectively customize the panel.

Detuning a standard or custom component is a lot easier and more cost effective than trying to build one from scratch. There will still be a customization up charge, and the inverse proportional curve of cost and volume will still apply, but the result may be more palatable. The strategy of starting with an existing component may make it easier and less costly to acquire replacement parts.

Tip 4: Find a Supplier Ecosystem That Brings Machines to Market Faster

Tips 1 through 3 focus on hardware. Tip 4 looks at the soft issues that spell the difference between buying satisfactory hardware and buying hardware that gives the design process spectacular outcomes.

Every company has a unique culture and product ecosystem. While cost, performance and availability may be similar among suppliers, their ecosystems may be miles apart. For example, one supplier may offer great delivery and a wide product line but provide little or no application engineering support. If application engineering from an expert in the component will make a better machine, then find a supplier that emphasizes both products and services. The ecosystem can have a profound impact on outcomes.

What should a designer look for in a supplier’s ecosystem? Start with a one-stop shop for multiple components. This will simplify the specification process. The learning curve will lessen when team members become proficient on multiple products from a single vendor. Look for ease of ordering, speed of delivery and ease of resupply. Suppliers that offer superior field support can save the machine builder time, money and labor.

The Festo Handling Guide Online engineering tool enables engineers to specify the drives, motors, actuators and accessories of a multi-axis handling system in as little as 20 min.

Online engineering tools decrease engineering overhead, as does the assistance of supplier application engineering support. Delivery of cost-effective subassemblies will decrease build time, which is an advantage when skilled labor is scarce. Commissioning software tools can save time and effort. For connected components, look for an architecture that is flexible, multiprotocol and adds plug-and-play functionality. It is also important that the supplier supports IO-Link. The designer may not presently use IO-Link, but the industry is moving toward IO-Link as a norm.

Selecting standard and custom components, using existing components as the basis for customization of parts, and engaging with a supplier ecosystem that brings machines to market faster and at less total cost will enable effective component selection.