TPT September 2011

A rticle

Figure 6

So what’s stopping you? As process consultant, AddisonMckee is often asked to advise clients on the amount of material required to bend a component or series of components. To facilitate a smooth ramp-up to production, AddisonMckee will typically play it safe in arriving at its calculations. This approach is obviously the safest way to avoid the unthinkable scenario of the consultant having to go back and tell the client that the twenty bundles of tubes he just purchased are an inch too short. However, and this is key, there still continue to be many examples where the initial tube length is accepted as gospel and never re-evaluated. With re-evaluation the cost savings can be very real and, just as importantly, very easy to make. Ultimately, though, the best money-saving strategy is the most basic of all: using your eyes. Simply look at the ‘off-fall’ coming from the first clamped end and ask yourself: “Does it need to be this long?” Run the bender to the end of the last bend, pause it, and look again. Then ask yourself “What’s stopping me from shortening the tube?” The answer may well be obvious and very simple. Nothing. The fortunes of AddisonMckee itself have certainly taken a turn for the better in recent months as the market climbs out of recession. New ownership has galvanised the company by introducing a number of measures to ensure a smoother ride for all its customers, in, among others, the automotive, aviation, truck and shipbuilding industries. First and foremost, while the company remains a truly global concern with partners all over the world, in response to overwhelming demand from its European customers, AddisonMckee has restored the manufacturing facility at its HQ at Bamber Bridge in the UK, a move that underscores the company’s commitment to its European partners not least by significantly reducing costs. Forming better strategies for all its customers

• WL = Wiper die length • CD = Collet depth • SLx = Straight length (where x is the last straight) • CF = Clearance factor (5mm) • ALy = Length along the arc (where y is the last bend) • LL = Limiter length (Distance from tangent at which the collet housing will encounter interference) Arc Length Formula: AL y = (Π * CLR / 180 * DEGREE OF LAST BEND) Limiter Length Formula: LL = WL (Pressure die length is not considered) Collet Stock Formula: LL + CF + CD – SL x – AL y Using the sample data: • LL = 100mm Note: If the calculated collet stock is a negative number and the last straight is less than 2D, then only add enough material to make the last straight 2D. If the calculated collet stock is a negative number and the last straight is greater or equal to 2D, then no additional collet stock material is required. Theoretical tube length The theoretical tube length is the sum of the three main components: clamping stock, component(s) stock, and collet stock: Theoretical tube length formula: Clamping stock + component(s) Stock + Collet Stock From the sample data: • Theoretical tube length (with boost) = 96.63 + 509.27 + 106.41 • Theoretical tube length (with boost) = 712.31mm • Theoretical tube length (without boost) = 96.63 + 509.27 + 30.41 • Theoretical tube length (with boost) = 636.31mm • CD = 30.15mm • SLx = 48.45mm • ALy = (Π * CLR / 180 * 50.79) = 56.29 Collet Stock = LL + CF + CD – SL x – AL y Collet Stock = 100 + 5 + 30.15 – 48.45 – 56.29 Collet Stock without Boost = 30.41mm

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S eptember 2011

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