13 CRITICAL STEPS to Ensure Metal Stamping Success

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OEMs that incorporate metal stampings in their products range from medical device and electronics manufacturers that need micro-miniature parts made from extremely thin material to automobile manufacturers requiring components made of high strength steel alloys. The insert molding industry also requires complex metal stampings that deliver high performance and tight tolerances. Although metal stamped parts may appear to be just a small component of the larger product, they can have a significant impact on a manufacturer’s bottom line in terms of costs, cycle time, and product reliability.

When designed and produced in the most cost-effective manner, metal stampings can help reduce product costs, cut production time, and enhance product life.

This e-book explains 13 steps that OEMs can follow to ensure their metal stamped part will perform to their exacting specifications.

HOW METAL STAMPINGS CAN MAKE ABOTTOM-LINE IMPACT

Step 1: GET IT RIGHT FROM THE START

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If engineers at metal stamping firms had just one wish to make the process go more smoothly it would be for the manufacturer to involve them very early in the part design process. Often times, CAD drawings are unrealistic and don’t take into account the limitations of metal stamping.

In fact, the metal stampings that perform best are based on Collaborative Product and Process Design, which allows the metal stamper to interpret the client’s specifications in light of optimal metal stamping design and production, including assessment of materials and part tolerances.

Metal stamping engineers may propose design improvements that lead to significant savings in production time and expense – from something as simple as changing the way parts are packaged to save on assembly costs to complex changes such

as reconfiguring a part to eliminate unnecessary steps in the overall manufacturing process and drive down expenses.

For example, one large manufacturer brought in representatives from all of their outside suppliers involved in producing a key component, including molders, stampers and electronics specialists, to design the parts as a team. As a result, the metal stamping was redesigned to make the part less expensive to produce and easier to assemble.

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Step 2: FORECAST YOUR REQUIREMENTS

It is best to be upfront about your anticipated requirements for the part and its final assembly, including your projected volumes and release frequency for the year. Talk to your stamper about the impact shipping frequency may have on overall costs.

If you share the full scope of the manufacturing process from how you assemble parts through the final assembly, the metal stamping engineers may be able to propose changes or redesign the metal stamping to reduce part cost and make it easier to manufacture. If the metal stamping engineer understands your assembly process, the part may be designed with features that will save on additional handling. For example, a metal stamping can be designed to stack at the press in the orientation you need to prevent secondary handling and reduce costs.

Your anticipated production volume has a bearing on how a stamping is produced and its cost. Low volume products do not require as robust tooling as do high volume products.

Manufacturers are often surprised by the amount of lead time required for a metal stamping. Although rush projects can be handled in a matter of weeks, a realistic manufacturing schedule should allow several months for part design review/modification, tool design, material orders, and production ramp-up.

Step #3: EVALUATE CRITICAL TOLERANCES

Tolerances in metal stampings are the permissible variations from a specification for any characteristic of the part, which can be a point of misunderstanding with manufacturers. Some OEMs will specify the tightest tolerances as a general rule, with the idea that tighter tolerances are always better and reduce the risk of part failure. However, the tighter the tolerance, the more expensive the part is to produce, because the metal stamper will have to spend more time developing the die and maintaining it to specifications. Of course, a good metal stamper will be able to achieve tight tolerances and high precision when required.

Manufacturers and metal stampers should work together to understand the importance of tolerances in metal stampings and how much variance will work for the part’s production process and end use. The metal stamper’s engineers can collaborate with the OEM’s engineers to determine the most critical areas of the part, as it relates to form, fit and function, and determine appropriate tolerances based on those criteria.

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Equally important is determining the appropriate dimensions of the part, and how the part will fit into its final assembly. If the metal stamping has to mate with another part or snap into place, those dimensions are critical. Any critical dimensions should be assigned accurate measurements and highlighted on the drawing.

To speed the time to market, the metal stamper may be able to design and run in-die assemblies to eliminate unnecessary steps in your overall production process and cut expenses.

In order to ensure that the part will function as required, the metal stamper will follow the requirements for the part approval process.

STEP #4: ASSESS THE DIMENSIONS FOR FINAL ASSEMBLY

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STEP #5: SET ACCURATE PRODUCTION VOLUMES

Whenever possible, manufacturers are advised to set realistic annual production volumes at the outset. If you expect variations in volume throughout the year, the metal stamper will need to be prepared for a flexible schedule. The manufacturer also may want to build up an inventory of parts in advance to meet demand forecasts.

Anticipated production volumes, together with the unique characteristics of the part, will determine whether you need manual assembly requiring specialized skills or fully automated or robotic-assisted assembly of multiple components. For a new product launch where demand may increase quickly, you may find it more cost effective to start with automation, rather than move from manual to automated production and incur additional costs. If volumes exceed expectations, the metal stamping firm may need to build a second tool to handle the extra volume. It is extremely important to share production volume upfront to determine whether a multiple up-die may be necessary.

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Manufacturers may specify materials in their request for quote without fully understanding how the material will react during the stamping process. The metal stamper’s engineers can assist in selecting the best material for the part’s long-term function and wear, based on their knowledge of the characteristics of a wide range of materials used for different applications, from beryllium copper to pre-plated alloys to noble metals. Different materials can be tested during prototyping and simulation to validate performance.

The standard lead time for most material orders is 10 weeks. With noble metals and high-demand metals such as copper, lead times for orders can stretch as long as 12 weeks or more, which needs to be accounted for in production schedules. Global lead times for materials, which vary greatly from Europe to Asia, must also be taken into account.

The type of material selected depends on the part’s end use and the amount of wear the part will experience. One automobile manufacturer wanted to replace a plastic part that was being damaged in car washes with a metal part of the

exact same dimensions. However, with the different properties of plastic versus metal, the part had to be redesigned as a drawn component.

In addition, the metal stamper can nest the parts to significantly reduce the amount of scrap generated in the blanking operation. The stamper may also make recommendations to save on material cost by slightly changing the design and not the function. The stamping engineer can also lay out the part to minimize the use of precious metals or recommend the use of spot plating to reduce precious metal costs.

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STEP #6: SELECT THE BEST MATERIAL AND MAXIMIZE ITS USE

Ferrous metals, which contain iron, are magnetic and have little resistance to corrosion:

• Hot-rolled and cold-rolled steel• Stainless steel• High-tensile steel• Low, medium and high carbon steel• Spring steels• Coated steel

Non-ferrous metals – which contain no iron and are more resistant to corrosion:

• Aluminum• Copper• Aluminum-clad copper• Aluminum alloys• Brass• Phosphor bronze• Beryllium copper• High nickel alloys

Noble and other metals – which resist oxidation and corrosion:

• Titanium - this is a non-ferrous material• Gold• Platinum• Iridium• Niobium• MP35N

Other materials:

• Mylar• Plain wire• Shaped wire

MATERIALS USED IN METAL STAMPINGS

STEP #6: SELECT THE BEST MATERIAL AND MAXIMIZE ITS USE (CONTINUED)

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STEP #7: PLAN FOR SECONDARY OPERATIONS

Plan ahead for plating and other secondary operations and rely on the stamper for guidance and oversight of the process. These operations should be scheduled so that they can be handled as soon as possible after stamping to speed cycle time. The metal stamping firm can be expected to oversee secondary operations and quality control on the manufacturer’s behalf.

SECONDARY OPERATIONS

• Heat treating x Loose piece x On reels

• Secondary tooling to trim parts or to form and cingulate at the customer location

• Welding and spot welding• Mechanical finishing, including sanding, grinding, polishing

and buffing• Forming and laser welding• Specialty cleaning and deburring• Passivation• Sterilization• Electropolishing

Finishes:

• Plating x Pre-plating x Post-plating x Spot plating x Precious and non-precious metal plating

• Painting, e-coat and other finishes

Assembly:

• Manual• In-Die

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STEP #8: EVALUATE SIMULATIONS AND PROTOTYPES

Manufacturers should take advantage of a metal stamper’s ability to provide 3-D part simulations and prototypes to improve manufacturability and reliability, when required. These capabilities allow manufacturers to test the design and functionality of component parts before investing in full production.

The prototype will be based on the latest design and prints, along with material specifications. The metal stamper can build a prototype tool to validate design, as well as employ simulation software to evaluate how the material forms under different conditions to produce the part. If the prototype/ simulation process reveals weaknesses, the tool can be redesigned to improve function, strength and manufacturability. Although extra costs are associated with prototyping, this step can be completed in just a few weeks and often prevents

costly problems during production and manufacturing. If the cost of a prototype seems prohibitive, the stamper can sometimes use simulations to evaluate the part design functional strength requirements and to optimize the part design to best suit the metal forming processes.

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STEP #9: PICK THE BEST PACKAGING

Consider the importance of packaging as it relates to the final assembly. The optimal packaging will depend on the characteristics of the part and how it will be used on the assembly line. Some parts can simply be dropped into bins as loose pieces while others should be packaged on a strip for automated assembly at the manufacturing plant. Parts that might get tangled must be packaged for easy access. In the same way, delicate parts that must maintain their exact dimensions should be packaged to avoid damage in transit or in handling for assembly. Cost considerations often dictate packaging, but the overall costs of shipping, handling, storage and processing must be taken into account. In addition, if the parts will be shipped out of the country, customs and export services will impact packaging requirements.

Packaging Options

• Reel to reel• Loose piece• Parts supplied on a bandolier• Labeling and bar coding• Reusable packaging• Special handling containers• Custom packaging• Export services• Tape and reel

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STEP #10: BUILD IN TIME FOR TOOL DESIGN

Allow time for tool design and development in the production schedule. Ideally, the stamper will have in-house tool design and build capabilities. Manufacturers may be surprised to learn that it may take anywhere from 8 to 26 weeks to create a custom tool depending on the complexity and development of the part.

Metal stamping engineers will take the manufacturer’s production requirements and key characteristics of the part into consideration when recommending the right design, taking into account the intended life of the program.

The technology that metal stampers may employ in the design and build stage includes:

• 3-D tool design and simulation software to develop complex tools

• In-die sensor technology to ensure consistent quality and reduce downtime

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STEP #11: PLAN FOR QUALITY WITH APQP

A metal stamper concerned with quality will follow the APQP (Advanced Product Quality Planning) process or a similar process to ensure quality from the outset.

The APQP process was developed by automotive manufacturers and involves their parts suppliers in every step of the development and launch process – from initial development through product launch and beyond. The APQP process monitors more than 20 areas before production begins, such as design robustness, design testing, quality inspection standards, product packaging, and more.

The medical device industry prefers DQ/IQ/OQ/PQ, which relates to verification and validation of both design activities and manufacturing process development to ensure that the device will function as specified. The processes are spelled out

in the ISO 13485 standard for medical device manufacturers, including Design Qualification (DQ), Installation Qualification (IQ), Operational Qualification (OQ) and Performance Qualification (PQ).

The initial quality planning phase adds time to the schedule but saves quality problems down the road.

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STEP #12: MONITOR QUALITY IN REAL TIME

Zero defects has become the norm globally. To ensure quality in metal stamping, the firm should employ statistical process control systems and in-die sensors to monitor quality in real time.

In evaluating a metal stamping supplier, ask for an overview of the technology in place to ensure quality and how frequently that equipment is used. The best metal stampers will employ quality control processes to detect potential problems in real time. Manufacturers can ask for quality reports as needed.

Quality Control Technology in Metal Stamping

• Statistical process control systems

• Optical vision systems

• Functional gauges and custom gauges

• Digital measuring machines with metrology software

• In-die detection systems

• In-die measurement systems

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STEP #13: KEEP IN CONTACT

It may go without saying that it pays to stay in close communication with the metal stamping firm. If you see the potential for changes in production volume down the road, it helps to alert the metal stamper to the possibility and talk over what preparation might be required.

A customer-focused metal stamping firm will assign a project manager/engineer as a single point of contact for all new programs. During production, a customer service representative would be assigned who knows the customer’s industry and unique business requirements. Once production is underway, it is advantageous to work with a customer service representative who understands the client’s industry and unique business requirements.

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THIS GUIDE WAS DEVELOPED BY KENMODE PRECISION METAL STAMPING

About Kenmode Precision Metal StampingSince its founding in 1960, Kenmode has built a reputation for strict adherence to uncompromised quality and performance standards in the manufacture of complex, high-precision custom metal stampings and assemblies for the automotive, electronics, consumer goods, insert molding, and medical device industries worldwide. Today, Kenmode fields one of the largest and most experienced engineering, design, and tool & die teams in the industry and employs the latest technology throughout the metal stamping design and production process. Kenmode handles a wide range of metal stamping materials and component parts, from micro-miniature medical stampings to large automotive stampings made from steel.

Kenmode820 West Algonquin RoadAlgonquin, Illinois 60102-2486 Tel: 847-658-5041sales@kenmode.comKenmode.com©2015 Kenmode