Extrusion International 6-2017

18 Extrusion International 6/2017 EXTRUSION TOOLING Getting the Most from Your Extrusion Tooling By utilizing state-of-the-art production equipment and processes, machining tolerances are held extremely close on today’s multi-lumen and multi-layer medical tubing. It is important to note that any misalignment of the tools may be exaggerated in the final product output Clean parts, especially with sealing and locating surfaces, are key to product performance and successful end prod- ucts. These surfaces receive the most care and attention during manufacturing and are the control surfaces that ensure uniformity throughout the tubing. Remember, pre- cision-machined alignments are affected by even a speck of dirt measuring only a few thousandths of an inch. A hu- man hair is about 0.003” (0.08 mm), and since there are many such surfaces in a quality tool, cleanliness is critical. Checking of the tools for any deformities is also important. Burrs, scratches and scrapes are usually a result of careless handling and/or storage of equipment. Double and triple- layer extrusion heads pose an even greater challenge for maintenance. The number of sealing and centering surfac- es multiplies and canmagnify the results of dirty tools. Dur- ing changeovers, the head may be disassembled in order to change compounds and/or tips and dies. Foreign mat- ter is usually introduced at this point and residual materials must be thoroughly removed. Physical tool damage often occurs during this phase, due to mishandling and poor storage techniques. These are highly precise parts, but can also be heavy and bulky to remove by hand. Use of a dedi- cated work cart exclusively reserved and equipped for ex- truder head maintenance is recommended. This cart along with a supply of spare components and hardware is easily justified, especially when examining the potential cost sav- ings that result from well-maintained tools. The following should be considered: • Maintain a clean, organized work area with soft and clean renewable work surfaces • Use a vise with soft jaws, such as copper • Use special equipment, such as tip removal tools, etc. • Standard tools include wrenches, soft-faced hammers, etc. • Maintain a supply of soft, clean rags • Use cleaning solutions in spray bottle • Use spare parts as suggested by your tooling supplier, properly organized and stored • Keep handy your equipment’s repair/maintenance manual • Have a small surface plate to provide a true flat surface • Use a set of appropriate gauge and tip pins for initial tool location adjustment •Make sure you have all the proper lifting aids available, including overhead hoists, hydraulic lifts, etc. In most situations, the head and tooling will still be at elevated temperatures, therefore lined gloves are needed when handling. Today, tubing manufacturers compete with companies all over the world. To be a successful and prof- itable company, quality and efficiency are essential. This is especially true in extrusion, where material costs are usu- ally much higher than labor costs. Like a racing car stuck in the pit, many extruders sit idle because of poor or dam- aged tooling, plus excess maintenance time. Overhead costs add up and losing money is the result. Some start up quickly and make scrap, whereas others start up and run a product oversized to hold minimum tolerance. They waste 10% to 20% of the material, which can run from 50% to 90% of the product cost. The tooling supplier goes to great lengths so that tips and dies are machined to a determined specification, ensuring perfect concen- Fig. 1: Double and triple-layer extrusion heads by nature have more sealing and centering surfaces