April 2019

n ROBOTICS Plastics moulder becomes its own robot installer T he Malvern-based injection moulder SynthoTec has been making precision plastic parts for almost 30 years. It produces bearing cages that are used in two main areas: heavy-duty rotating mechanical and electrical applications, such as alternators, air conditioning, and HGV axles; and lighter weight, yet durable, precision moulded parts for products such as child seats and power tools. The company supplies plastic cages to global manufacturers of rotating and linear bearings, such as SKF and NSK. It produces these cages in diameters from 20–250mm, as well as designing and producing even larger custom versions. In early 2018, the SynthoTec management team, led by managing director GrahamWard, decided to install robots in its bearing cage demoulding cells.“We wanted to move the production cell forward to a new concept, and a six-axis robot enabled us to greatly simplify the cell,”Ward recalls. The company wanted the robot to take cages from the mould, hold themwhile the waste sprue was dropped into a recycling granulator, and then place the finished cages onto pallet-mounted mandrels. Each mandrel needs to be stacked with up to 185 completed cages and the robot would have to feed more than 150 close-packed mandrels in succession onto each pallet. The engineering team set about designing an installation that would update its cells and embrace the latest developments in robotics. By using an off-the-shelf multi-axis robot, the company could make significant savings by reducing wastage, cutting process times, and reducing the number of moving parts in each cell by one third. It also took the opportunity to reduce the number of PLCs used to just one. Having established what was needed, the team decided to do something unusual – to design, install and commission the robotic cell itself, using its own team of design engineers, production engineers and toolmakers. Proven track record The company already had a proven pedigree in making and installing its own machinery wherever possible thanks, in large part, to the skills of two experienced automation engineers, production engineer Jon Hart and operations director WayneWilliams. Usually, an OEM calls in a robotics partner in the form of a manufacturer or integrator, briefs them, agrees commissioning dates and prices, and lets the partner get on with it. SynthoTec was adamant that it wanted to do the job itself. “Robots are an integral part our business, as is our desire to continue developing in-house automation solutions to exactly meet our own needs,”explains Ward.“It is just one of many facets that allows us to retain absolute responsibility for the quality of end-product for which our business is respected. We take this reputation extremely seriously and therefore sought a robot supplier prepared to work on our terms.” After meeting several potential suppliers, the SynthoTec team opted for Kawasaki Robotics’ RS-20N medium-duty robot, which offered the required high speed in every axis, and could demonstrate repeatable accuracy to within ±0.05mm for each axis for the lifetime of the robot. The arm has a 20kg payload, a horizontal reach of 1,725mm, and a vertical lifting capability of 3,078mm. Even though it is regarded as a high-speed machine (its wrist can twist at 610 degrees per second, for example), the robot achieves a repeatable A UK manufacturer of precision plastic parts has taken the unusual step of installing and commissioning its own robots, rather than using an integrator or robot supplier. It says the decision has allowed it to boost production, cut costs and achieve a significant reduction in waste material. POWER DISTRIBUTION ENCLOSURES CLIMATE CONTROL Enclosures from the smallest to the largest.