Problem solving Complete removal of long shavings from machining process
Extractor unit for plastic machining process Machining plastic is not like machining metal. Plastic has its own rules. Depending on the toughness and strength of the material being worked, machining plastic often produces long shavings. Long shavings can wind round the machine tool spindle or the workpiece, upsetting machining precision, clogging the machine and in some cases even stopping the process cycle. The problem is relatively easy to solve as the case of Wilms in Bad Essen demonstrates. This company machines plastic piping for pipelines. Pipeline sections are laid and joined end-to-end; joints must be fully leakproof. This means that the pipe ends must be machined to a high degree of precision. Pipes are machined on a CNC turning machines. The shavings produced during turning are extracted directly at source to prevent them from colliding with the workpiece or clogging the machine spindle. For this task, Ruwac-Industriesauger GmbH, working in collaboration with pipe-maker Wilms, developed a tailor-made solution using standard components. The shaving is vacuumed up directly at the workpiece. The vacuum required to do this is provided by a standard Type SA 2520 vacuum unit. The material extracted is fed to a pre-separator container mounted about three-metres high on the wall. During turning the shaving warms up and becomes flexible. However, it quickly cools down to form a bulky, spiral-shaped piece of waste. This is the reason why at the end of each machining cycle a pneumatically controlled flap on the pre-separator opens and empties the pre-separator contents into a large waste container below. The shavings are collected here ready for recycling and to be returned to the material cycle. The extraction plant controller is connected to the controller of the CNC turning machine. When a pipe is clamped in the turning machine and machining starts, the extraction plant is automatically switched on, too, ready to vacuum up the first shaving. The signal to stop the extraction plant and to empty the pre-separator also comes from the turning machine. The extraction plant therefore only runs when there are shavings to be extracted. A box filter is mounted upstream from the vacuum unit and holds back any fine dust or dirt. The sound-proofed unit is driven by an AC motor, develops a vacuum of 2500 mm WS and has an air flow rate of 640 m3/h. The plant has operated trouble-free since installation and is to the customer's complete satisfaction. Ruwac designed this particular plant on the basis of the experience and expertise gained in similar projects. One of these was an extraction system for vacuuming up a continuous, 20-metre long strip of shaving produced during the precision machining of PTFE blocks. Ruwac experience and expertise means two things. First, our production range is modular so that designing a system is simply a question of mixing and matching the right standard components. Second, customers get systems fully tailored to their individual requirements. Our solutions are more cost-effective, too. |
