Extrusion International 2-2022

29 Extrusion International 2/2022 Standard tools include wrenches, soft-faced hammers, etc.; 5.) Maintain a supply of soft, clean rags; 6.) Use cleaning solutions in spray bottle; 7.) Use spare parts as suggested by your tooling supplier, properly or- ganized and stored; 8.) Keep handy your equipment’s repair/mainte- nance manual; 9.) Have a small sur- face plate to provide a true fl at sur- face; 10.) Use a set of appropriate gauge and tip pins for initial tool location adjustment; 11.) Make sure you have all the proper lifting aids avail- able, including overhead hoists, hy- draulic lifts, etc. In most situations, the head and tooling will still be at elevated temperatures, therefore lined gloves are needed when han- dling. Today, tubing manufacturers competewith companies all over the world. To be a successful and pro fi t- able company, quality and ef fi ciency are essential. This is especially true in extrusion, where material costs are usually much higher than labor costs. Like a racing car stuck in the pit, many extruders sit idle because of poor or damaged 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 deter- mined speci fi cation, ensuring per- fect concentricity and alignment. The material is then distributed in the proper location as part of the fi nished product. Understanding Maintenance Procedures: Get Organized Before You Start Example1: Inthis example, with an improperly centered tool, a calculated out- of-tolerance area of 0.059 in2 (38 mm2) was derived. When the two surface areas were compared, the calcu- lated material waste was 11.8% of the fi nished product. The formula is % wall = min. wall thickness, max. wall thickness X 100. Example 2: Alternatively, if the % wall can be increased from 80% to 95%, a sav- ings of about 12% of total cost can result. Savings will vary depending on the designs, of course. Get help for heavy parts and awk- ward situations. Surfaces and edges are hard and therefore somewhat brittle, so dropping a part or strik- ing parts together can result in dam- age. Store your tools properly in a dry, clean area – a dedicated spot for each tool is best. These areas should have soft surfaces and each instrument should be covered after cleaning. Also, tools should be seg- regated so that they do not come into contact with each other. And tools and all instruments should be cleaned thoroughly before storage. For disassembly of tools, it is imper- ative to use purpose-built tooling to facilitate disassembly. These should be available from your supplier. If they are not, consult with a reputa- ble tooling house for replacements. The cost of these tools is easily offset by potential damages, frequently caused by improper equipment such as hammers and drifts. Follow the guidelines outlined in your opera- tor’s manual. Individual tools may have speci fi c recommendations, so contact your supplier if anything is unclear. Your supplier understands that optimum performance relies on proper care and maintenance. Here are some useful tips: 1.) Clean your equipment while it is still hot as the residue is easier to remove. It helps to remove and clean one piece of tooling at a time in order to maintain elevated temperatures. 2.) When cleaning a dual compound crosshead, (plastic and rubber) clean the plastic tooling fi rst; the rubber second. 3.) Never use steel tools such as scrapers or screwdrivers because these can scratch and mar the tool- ing. 4.) Do not use open fl ames be- cause this generates excessive heat especially in thin sections, which can affect hardness, concentric- ity and tolerances of components. Recommended cleaning tools and materials include: a.) Brass pliers to grip material and aid in pulling; b.) Brass scrapers available in different widths for cleaning fl at exposed sur- faces; c.) Brass bristle tube brushes that are available in diameters from 1/16” to 1” in 1 /16” increments (ide- al for cleaning holes and recesses); d.) Brass rods – different diameter rods are good for pushing material out of fl ow holes; e.) Copper gauze for cleaning and polishing exposed round or conical surfaces; f.) Copper knives for removing residue from recesses and other hard-to-reach areas. Also, polishing compound restores polished surfaces; g.) Com- pressed air, which is more effective for releasing plastic, but also aids in rubber removal. Be careful not to force debris into recesses with compressed air; h.) Cleaning solu- tions may be useful, so remember to use fresh, clean rags (used rags often have metal chips embedded in them, which may scratch polished surfaces); i.) Cleaning oven – for plastic only. Follow manufacturer’s recommendations. If no tempera- tures are speci fi ed do not exceed 850 degrees F (454 degrees C). Don’t quench tooling to cool, as this could affect tooling hardness, con- centricity and tolerances. j.) Purging compounds – several are offered to purge the extruder screw/barrel of residual polymer and rubber com- pounds. Removing Excess Material for OptimumMachining Ef fi ciency Clean parts are critical to extrusion tooling performance and quality manufacturing. This is especially Guill Kelpac