Part Proliferation, Why it takes away your competitive edge? Part 3: Fasteners

Last Blog we looked at ways to cleanup parts off the inventory as well as the ripple effect this cleanup may have on your bottom line. In this Blog we will look at fasteners. They can have an immediate impact on design, supply, and manufacturing total cost when standardized.

Influence of Fastener,

Fasteners have been around for centuries; in all shapes or forms and materials, for all kind of applications. Typically, the application is what drive the selection of a type of fastener, the environment is what drives the material selection. There are however other factors that will influence the selection of a fastener: The tooling available on the factory floor and method used (robots, auto-feed screwdrivers, manual installation etc.) to install the fastener will also have a predominant influence on the selection, and these factors are often forgotten, only to be figured out during critical design reviews when 90% of the manufacturing cost has been committed by design.  Although fasteners are typically the smallest and the least expensive components in an assembly, if they are not properly selected and standardized, they can prohibitively drive up the cost of assembly, therefore compromising the competitivity of the product on the market.

Consideration in selecting fasteners,

Companies should develop their own considerations based on their manufacturing process and products that ultimately leads to the selection of a fastener or group of fasteners for a given application. One cannot arbitrarily select a fastening system without answering (at least) the very basic questions listed hereafter and incorporate the answers in the design. Selecting the fastening system for a given product early in the design process will lead to a conscious decision that will have an impact on the committed cost of manufacturing:

Application: Aircraft, Marine, Space, Bridge, Building, Furniture, Electronics etc...

• Load Case: Tension, Shear, Fatigue…
• Limitations: Structural, Non-Structural, Fatigue, Creep, Secondary Stress...
• Environment: Corrosive, Liquid, Space, Temperature, Salty...
• Type of joint: Fastened, Bonded, Permanent, Structural, Non-Structural...
• Joint Material: Metal, Plastics, Rubber, Concrete, Wood, Composites, Dissimilar materials...
• Number of fastening components: Screw or bolt only, washer needed, nut needed, Inserts, nut plates, self tapping...
• Installation methods: Manual, Mechanical, Quick Turn, Robotics...
• Tooling: Auto-feed, manual, robot, jigs, special tools, power tools, Access...
• Access: From top, from bottom...
• Security/Safety: Lock-wire, lock features, vibration, loosening, fatigue...
• Fastener hole Type: drilled, tapped, self-tapping…
• Fit: Clearance, loose, Press-fit...
• Head Design: Flat, Hex, Fillister, etc….
• Drive: Slotted, Hex, Philips, Robertson, Hex Socket...
• Size: Diameter and length...
• Availability: Stock, COTS, Custom...
• Fastener initiatives

Initiatives in fastener standardization will have a significant impact on total cost. Obviously the least expensive fastening system is no fastener at all, but this is another subject. The easiest way to limit fastener types is to impose a limitation on designers and educate them on what is preferred from a manufacturing point of view; the Designers are the ones selecting the fasteners. One easy way to do this, is by creating boards showing the preferred and accepted fasteners, but with today’s CAD systems, coupled with Fastener managing Systems such as SynchroFit – Vistagy and Cenit AG,  the preferred fasteners and what is common stock can be modeled and kept in a library that is linked to the Master BOM, giving full visibility to designers of what is available at all time.  In fact, Designers should always design with what is available on the factory floor. Any new fastener introduced to the factory floor should be thoroughly analyzed as the impact on factory activities can be significant.

The Ripple Effect

Minimizing the types of fastener in inventory will maximize the buying power, therefore lower cost via an economy of scale. The effort and cost to create a library and database will pay for itself in time saved in engineering, but mostly in time saved on the factory floor.  Further initiatives should thrive at designing for the least number of fastener type, and even to design for no fasteners when possible.

Closing Comment

It is a known fact that fastener types have proliferated in product development, to the point where the true selection criteria's are becoming blurred.  Understanding the influence of fasteners and how we select them will lead to significant savings on the total cost of product development. It is worth putting the effort to create initiatives that will lead to a more judicious use and a better selection of fasteners, while reducing cost.

Part Proliferation, Why it takes away your competitive edge? Part 2.

Last blog we looked at what causes part proliferation and why it takes the competitive edge out of companies. In this blog we will look at solutions that can potentially help manufacturers to reduce their inventory of parts sitting in the warehouse.

Standardization of parts,

The best way to avoid proliferation is through standardization of parts. For a company that has a legacy of parts a thorough analysis of all parts must be performed to create groups and families of parts to clean up the system. Parts that are the same must be consolidated into one part number. Parts that are similar in shapes and function can be consolidated into one part which can then be modified as required. Creating a Standard Bill of Material (BOM) of preferred parts and making it easy to consult using Off-the-Shelf applications will control and avoid the proliferation of parts. Unfortunately an iron fist is required to maintain a cleaned BOM, and this doesn’t mean that the system has to be inflexible, but rather the opposite. The flexibility is created through the designing of parts that can be modified for multiple purposes when required or the simple reuse of engineering or designing around Off-The-Shelf parts. It all starts at the very beginning in the definition phase of products.

The Zero-Based Approach,

In the previous blog we referred to this approach as the Empty Drawer or Empty Room concept. Dr. David M. Anderson has developed a similar method to reduce and cleanup parts off an inventory. The Zero-Based Approach is based on the principle of: “What is the minimum list of parts type we need to design new products”. This approach literally starts at zero and adds only the parts that are truly needed from an overwhelming list. It is like emptying a drawer and just put in what we want, rather than taking out what we don’t want. The latter takes more time as wanted and unwanted items are cluttered together. The exercise of cleanup your BOM using the Zero-Based approach must be done with a vision of developing products with a minimum of parts that can be reused in different designs.  Obviously once this is done, a decision has to be made as to what will be done with the unwanted parts. Again, don’t send then back to the store room.

Designing for Standardization,

Standardization must be designed into the product. Designing for standardization, other than engineering a product, is in fact a consolidation of activities aimed at defining, evaluating availability, purchasing, and sustaining supply of parts during the concept phase in the development of a product. Before any lines are drawn on a CAD, the use of preferred parts, reusing already designed and tested parts or designing new parts is defined in a concurrent manner involving at a minimum; Engineering, Supply Chain Management and Manufacturing. This trio must reach a consensus on parts; their supply and how they will reach the production floor on time, without inventory, and zero Work-In-Process (WIP).

The compounded effect of working in a One-Piece-Flow environment and Standardization will virtually eliminate inventory and completely eliminate WIP, therefore resulting in substantial financial savings, and product out to the customers faster.  

The Ripple Effect,

Standardization has a ripple effect on the operation of a company that develops products. The financial savings will come in the forms of: No inventory to support, less parts means less  effort to purchase, better purchasing leverage due to a higher volume of the same parts ordered, reduced floor space means no need to expand to have more room, less overhead cost, better quality due to a lesser number of different parts to support. Having the product to the customer faster also means better financial returns and repeat business. It also means that supplier will have savings as well as they will supply a higher volume of the same parts, therefore passing savings onto the customers to repeat business, yet still be profitable.

Closing Comment,

Companies that have adopted standardization as a mean to control their part proliferation have seen their inventory, and WIP virtually eliminated and Total Cost reduced, making them more profitable and competitive than they were before, and allowed them to develop new products better and faster. Standardization is not something that is technically complex, but will require leadership and vision. Cleanup the system using a zero-based-approach is a fast and simple method to create a BOM of preferred parts. Professionals like Dr. David M. Anderson have proven that standardizing parts, the total cost of developing and producing products is dramatically reduced, and the exercise typically pays itself within 3 financial quarters.

Part Proliferation, Why it takes away your competitive edge

Part proliferation happens out of ignorance, due to lack of guidance, proper design policies and supply chain knowledge. Most product designers (especially young ones), do not understand the importance of part standardization and the cost savings associated with it, as they are concentrating more in modeling parts on their CAD than understanding the whole system that surrounds product development. The author of this blog had a customer who had a major problem with part proliferation and it is due to the three causes listed previously. These causes have a ripple effect on the total operation and the total cost of the product. This happens because the Product designers don't spend the time looking for existing parts. As Dr. David M. Anderson says in Design for Manufacturability and Concurrent Engineering, "Never design a part that you can buy off the shelf".  Product designers are the one controlling the BOM’s and if they don’t have this understanding, proliferation starts as soon as they start modeling the next project.

Why it happens?!

As we have already mentioned there are three basic causes of part proliferation, but we can easily list a slew of causes.

Simple part fallacy: Product designers see some parts as being simple to model, therefore simple to fabricate, therefore inexpensive.

 Inexpensive part fallacy: product designers see hardware (screws, bolts, nuts, rivets …) as being inexpensive, yet the cost of maintaining an inventory of multiple fasteners to suit everyone's taste can drive production cost up exponentially and drive efficiency down exponentially.

Lack of global thinking: Sometimes Product designers fall in the trap of Not-Invented-Here, and will design a part that is probably available of the shelf.

Arbitrary decisions: Product Designers will often specify or design a part that does the job (but not more) for their specific application, when a standard part in store but a bit different may do the job, but is not chosen because of size, shape, or material.

Lack of Standard BOM: Many companies decide to create their Standard BOM as products are being developed without a clear policy, resulting in all of the above. 

Strategy

If one starts a new line of product it is quite easy, however if one deals with an on-going product, strong leadership and time will be required.

The first target should be the elimination of duplicate, triplicates… and then evaluate if some parts can be grouped into one basic configuration that can be modified as needed.

The second target should be aggressive fasteners standardization.

The third target should be working with Supply Chain Management to create a preferred parts list that is as complete as can be, and if parts need to be added, authorization is required.

One way of performing a consolidation of parts, is the Empty Drawer Concept or also called the Empty Room Concept. The concept is very simple. Empty the drawer of all its content (in our case the store room) and only put what you really need. What you don’t need is either sold or disposed of; regardless of the disposal means, you do, don’t put it back in the store room.

Closing Comment

It is proven that part proliferation increases cost in product development and manufacturing as it impacts efficiency and profitability. If one needs to compete with manufacturers from less than low wage countries, we need to re-invent ourselves in the way we approach product development, and how it should be manufactured by eliminating the waste and cost that we assume being part of the game of developing products. Some part proliferation elimination projects have paid themselves within one quarter (3 months), and have generated further savings from an economy of scale.

Welcome to Design for Purpose, a blogging site where experiences and knowledge on Design for Manufacturability (DFM) can be shared. Anyone who is serious about improving his or her design capability in DFM should join this blog and share knowledge with others who will also share knowledge.

One cannot expect to know it all and the pressure of being short staff adds to a well developing Burn-out. If we are too busy when times are bad and still too busy when times are good, when do we have time to increase knowledge to become more competitive? Competitivity is not reached by cutting staff, cost, and strangling suppliers. Competitivity is reached by acquiring knowledge that will make us more efficient.

DFM is a philosophy to achieve excellence by designing quality into the product. When considering that 60% of your fabrication cost is committed by design when you reach PDR, it makes sense to spend that time defining how the product will be produced, as further down the design process it becomes more and more difficult to reduce cost.

DFM is important to implement because the majority of manufacturing defects occur due to design-related issues. The success in creating a “manufacturable” product depends upon clearly defining product goals reflecting physical and functional requirements of the customer. Products designed using DFM philosophy will allow the following added values:

• Virtually defect-free or robust product design 
• Waste-free manufacturing 
• 100 percent usable COTS
• Minimal maintenance and service 
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