The material characterization is part of Roctool’s ongoing effort to further develop its High Definition Plastics material database which is designed to help OEM’s achieve exceptional part quality and increased performance” comments Mathieu Boulanger, Roctool CEO. “Roctool’s H&C can have significant effects on surface quality; it also helps to eliminate evidence of weld lines and flow marks. Mold cavity surface is heated very quickly up to temperatures that can exceed 200°C just before injection. The surface is then cooled quickly, to achieve the necessary demolding temperature to minimize any increase in total cycle time.” continues Mathieu Boulanger.

BP&R sat down with Gabby Day, communications manager at Pentagon Plastics, to discuss Pentagon's post-moulding procedures for adding features, maintaining quality control, and alignment with sustainability goals.

Shrinkage affects the physical size of the mould form and is a key consideration when designing a mould tool. Even within the same range of polymers they can vary due to different factors one such factor being additives, or fillers. Fillers such as Talc and Glass fibre are common in materials and much like clamping force the shrinkage of materials can vary greatly so it is important to know not only the polymer that is to be moulded, but the specific material grade as well.

Stephen has been with PlasticsToday and its preceding publications Modern Plastics and Injection Molding since 1992, throughout this time based in the Asia Pacific region, including stints in Japan, Australia, and his current location Singapore. His current beat focuses on automotive. Stephen is an avid folding bicycle rider, often taking his bike on overseas business trips, and is a proud dachshund owner.

Processes beyond the mould are secondary operations to the injection moulding of the part, usually carried out for component features that are not compatible with the moulding process but are necessary to the finished product or to keep some of the initial cost out of the mould tool.  This includes things such as drilling or insert fitting, milling, trimming and light assembly. Within the department quality checks take place every 1-2 hours whereby sample components that are being worked on are taken by the quality inspectors, checked, and measured using equipment such as co-ordinate measuring, callipers, micrometres, pin/thread gauges, and custom-built product specific jigs or gauges.

The Deltron features fully sealed recirculating bearings delivering four key benefits: no dirt ingress, no gearbox, no compressed air, and smooth fast operation. This helps deliver exceptional accuracy, simplicity, and reliability. The system will allow us to perform high accuracy measurement supported with bespoke generated reports, run automatic measurement programs, and allows offline programming. Having the ability to import DXF, STEP and IGES files will further aid the process and simplify the measuring of component parts.

Acrylonitrile-butadiene-styrene (ABS) polymer and blends supplier Elix Polymers reports that significant surface finish improvements are being achieved by using Roctool’s Heat and Cool technology to mold its Elix Ultra HH4115HI ABS/polycarbonate (PC) blend. The company recently completed a series of tests using this technology, carried out in line with its strategy of providing tailor-made solutions and service to companies processing its specialist materials.

Processing properties of the polymer dictate what temperature the tool needs to maintain during moulding. Some polymers require very cold tools, this is achieved by running chilled water through the tool and inserts, while others can require heating over 200°C, which is often achieved with hot oil or sometimes on smaller tools electrical heaters built in.

Pentagon operates under ISO9001:2015 standards spanning both mould tool manufacture and plastic injection moulding and quality is vital throughout our manufacturing processes.  The recent investment in to the Deltron CNC Coordinate Measuring Machine advances our quality process to the next level for mould tool manufacture. The compact machine brings high level measurement accuracy and repeatability directly to the shop floor allowing the technicians to check their own work at every stage and to produce extensive reports when required.  Saving measurable amounts of time on the existing manual processes this state-of-the-art technology will predominantly be used for electrodes, cores, cavities, and other tooling components it will deliver greater accuracy for quality checking.  The investment will support the reduction of tool manufacturing lead times and reduce the additional resources for reworking or remaking items.

Properties of thermoplastics are a key factor when designing an injection mould tool and the tool designer must take into consideration multiple factors that can vary greatly from polymer to polymer. The main ones to consider are camping force requirements, shrinkage, corrosive or abrasion properties, and mould temperature.

Considering optimal cavitation, cooling, and ejection systems that best align with the product material specification will mitigate the generation of plastic waste in the moulding process. With the continuing advancements in recycled polymers and their improving compatibility with the plastic injection moulding process there is tangible ethical progress for the plastics sector. Here at Pentagon, we are excited to be taking this journey in the next chapter of plastics processing and its contribution to wider environmental and economic sustainability.

Pentagon’s breadth of processing knowledge delivers multiple benefits to customers, sound material advice within the design stage coupled with optimal mould tool design that is aligned with specific material behaviours and properties. Our optimised injection moulding processes allow for manufacturing efficiencies that lead to repeatable quality products delivered with efficient lead times.

Superior surface replication, longer flow length, and lower pressure drop can be achieved with a combination of Roctool and Elix’s ABS/PC grade.

“Elix Ultra HH4115HI ABS/PC is now included in the HD Plastics material database based on the excellent results demonstrated by the characterization. The outstanding properties of this material will help us select Elix Ultra HH4115HI ABS/PC as an excellent candidate for upcoming projects with OEM’s.” explains Jose Feigenblum, Roctool’s CTO.

In line with the modern environment and the hard focus on sustainability within the polymer industry, the current crop of recycled materials that are available are much better than the products of a few years ago. Benefiting from much greater consistency allowing for a repeatable process in the moulding machine. This in turn increases our confidence in offering them as an alternative to traditional virgin polymers. This is particularly attractive to customers who want to be more environmentally sustainable or are simply looking for ways to reduce costs on high-volume parts.  Although our approach to injection moulding remains consistent this advancement in recycled material options does enhance the polymer industries offerings.

Depending on the chosen polymer and size of product the clamping force required to successfully mould the component can vary greatly, materials such as Low-Density Polyethylene require low force, while Polyether Sulphones and Polysulfones could require 13 times more clamping force. This will affect what press size is needed to mould the component in production.

Due to the chemical construction of some polymers and the additives, the tool designer may need to choose specific grades of tool steel for construction of the inserts to maximise the life of the tooling. Polymers such as PolyVinyl Chloride (PVC) release corrosive gasses during processing which can chloride steels with lower chrome content (non-stainless). While some materials require high hardness tool steels due to the abrasive properties or those of fillers that are added.

“HD Plastics characterization highlighted the improvement made by using Roctool technology with surface quality improved by the level of gloss and the black intensity. Indeed, Roctool’s technology allowed a reduction of the color lightness and we obtained a ‘piano black’ part with a perfect surface finish.” says Abad. In addition, replication of the textured surface was improved by over 50%, and there were significant improvements for each type of surface structure, especially with low roughness.

By heating the mold temperature above the glass transition temperature, an excellent cavity surface replication is achieved–even for surfaces that have the finest laser-etched grain structures – as well as the elimination of weld lines and sink marks. It therefore reduces or even eliminates the need for painting or in-mold decoration. Furthermore, shear stress in the melt is reduced which can have an important effect on the mechanical properties of the part and thinner walls.

Materials with glass filler offer benefits of improved strength, structural rigidity, and dimensional stability. Glass-filled nylons also have lower moisture absorption and are therefore less prone to taking in moisture compared to unfilled nylon, which can help ensure greater dimensional stability and reduce the risk of part failure in high-humidity environments.  Material selection is largely based on the parameters surrounding the end use of the plastic component and the environment in which it will be used.  The versatility of thermoplastic materials is advancing all the time which offers customers and their design engineers a wealth of options.

We are also using materials with carbon or steel fillers that make them semi-conductive. This can be useful in environments where static electricity can be an issue, providing Antistatic & ESD protection, preventing electrostatic discharges. Some conductive plastics are also used in Electromagnetic Shielding, reducing EM interference.

“We are operating in a highly competitive market, so it is important for us to go the extra mile to demonstrate to our customers how they can get the most out of our materials,” says José Pedro Abad, business Development Manager Automotive at Elix. “We wanted to quantify the possible improvements – in terms of part aesthetics and also processing performance – using Heat and Cool technology. We chose to use Roctool induction heating technology to characterize our innovative ABS/PC blend Elix Ultra HH4115HI, a leading Heat and Cool technology (H&C), in order to expand the already wide range of applications.” continues Abad.

The results are then recorded and monitored; this enables the quality team to see if overtime any changes have occurred and maintains consistent accuracy of post moulding operations.  The strict quality processes allow us to capture, report and rectify any quality concerns before they become an issue that may impact fulfilment of a customer order.

Elix Ultra HH4115HI ABS/PC, which was introduced just over a year ago, has several advantages over a PC/ABS (which contains less ABS and more polycarbonate). For example, it is around 5% less dense, it has lower emissions and odor, a higher flow rate, and higher impact strength. It is suitable for crash-relevant parts such as interior trim and parts that may be subject to knee or head impacts, as well as for exterior applications such as pillar covers and other painted side moldings.

Pentagon has been processing high engineering grades of thermoplastic materials for more than fifty years and the use of fillers greatly increases the choice of materials available to our customers and can provide advancements to the final function of the finished product.

The final HD Plastics characterizations are based on the study of the flow using the Spiral mold for thicknesses of 1 and 1.5 mm. This study shows substantial improvement using Roctool technology versus conventional technology in terms of pressure drop reduction, which is up to 60%, and flow length, which rises by up to 100%.

By working with experienced mould tool manufacturers such as us, sustainability in plastic injection moulding starts with mould tool design.  Mould tool design is a complex area and by working with experienced and expert tool designers your tool can be designed with minimised waste in mind at every stage of the manufacturing process.

To characterize the innovative ABS/PC blend Elix Ultra HH4115HI under H&C conditions and according to the HD Plastics process, Roctool determined the surface replication for the following three surface structures: Chemical grain; electric discharge machining (EDM) grain; and laser grain as well as improvements in gloss and color. Besides surface replication, flow length studies were also carried out.