At this year's K show, Italian hot runner specialist HRSflow will focus its presentation both on hot runner solutions tailored to the injection molding of complex, large-format parts with multiple gating in the mold and on systems for multi-cavity applications. Practical examples will feature the state-of-the-art FLEXflow technology, a servo-driven finely regulated valve gate system. The advantages of this technique, which is particularly suitable for cascade injection molding, include noticeable improvement in the surface quality of large-format visible parts but also maximum reliability in the series production of large, thin-walled transparent headlamp lenses. The FLEXflow technology permits an accurate process control, and a clear example is the welding lines management. Additionally at the K show, HRSflow will for the first time showcase their new ECOflow line, focusing particularly on high energy efficiency.
The Multitech product line – in which HRSflow has expanded hot runner solutions for multi-cavity molds – the company will present new hot runner nozzles of the MTR range, designed for both thin-wall and thick-wall injection molding processes.
Additionally, visitors of K show will be able to see the advances of the partnership between HRSflow Multitech and Plastic Technologies, Inc. (PTI), a global leader in plastic packaging development for single-serve beverage and food capsules.
FLEXflow precisely controls melt flow fronts
Remarkably with the cascade injection molding process, the electrically driven system of the FLEXflow technology allows the precise, sequentially coordinated opening and closing of the valve gate pins with selectable profiles and velocities. This in turn permits accurate control of the flow rate in each individual hot runner nozzle and subsequently of the flow front in the cavity as a whole. A significant example is represented by the weld lines management, in which throttling the desired valve gate pins makes it possible to perfectly control the shape and the progress of the flow fronts into the cavity, managing form and position of the resulting weld lines.
With the gentle opening and shutting of the valves, the dreaded pressure loss that occurs with conventional cascade injection molding methods through the abrupt sequential switching-on of the hot runner nozzles is avoided thus, with this, the accompanying flow marks on the molded part. Through a more even pressure distribution on the part obtained with appropriate position and speed control of central and peripheral valve pins, the FLEXflow technology also offers the possibility to reduce the requested clamping force and to eliminate the extra-part weight generated by over-packing.
In the automotive field, this electric- driven solution provides advantages in particular with the injection of large-area exterior and interior parts such as bumpers, spoilers, instrument and door panels, roof frames and also lighting and glazing parts such as headlamp lenses and roof panoramic panels.
Applications for the FLEXflow technology, which have been developed for series production in cooperation with project partners in the fields of polymer materials, moldmaking and machine manufacturing, will be presented at several booths at the upcoming K:
- Engel stand in Hall 15, Stand C58, the injection molding of a high-quality grained interior trim demonstration part, realized with the In Mold Graining technology coupled with the back injection of PP in muCell foaming process through five FLEXflow drops.
- Sumitomo (SHI) Demag stand in Hall 15, Stand D22, the production of a front headlamp lens made of transparent high-molecular weight PC by cascade injection molding with five FLEXflow-controlled hot runner nozzles on a full electric IMM – a 100% electrical driven solution.
- IKV Aachen stand in Hall 8B, Stand E61, the production of a road racing saddle (lot size of one) with the properties individually adjusted to the cyclist's personal characteristics – an intelligent product on demand, being a key aspect of Industry 4.0.
- Woojin Plaimm stand in Hall 15, Stand D58, the innovative solution to realize in one shot a chromed grill including multiple components with a 10 points-gating FLEXflow – a perfectly balanced solution for family molds.
ECOflow saves energy, reduces lead time
With the new ECOflow hot runner system, HRSflow has been able to reduce the energy consumption by around 20% compared with a conventionally designed system, 25 to 30% compared to systems in the market. At the same time, a very homogeneous temperature distribution is achieved in the hot runner. The time taken to reach a uniform and stationary operating state is also much shorter. The weight and volume of the manifold have been lowered by a third so that a smaller cut-out is also needed in the mold.
MTR hot runner nozzles for multicavity large scale production
In the multicavity sector, HRSflow Multitech offers hot runner solutions for injection molds designed for large-scale production of packaging, caps and closures, articles for medical technology, electrical and electronics, and the automotive industry. The focus here is on high cavity numbers, short cycle times, homogeneous balancing, and rapid color changes. The new MTR hot runner nozzle is available in three specifications: MTR-T, MTR-M and MTR-S. Their common distinguishing factor is the high resistance of the nozzle tip to wear and tear.
- MTR-T nozzle is specifically designed for the injection molding of large containers with wall thicknesses as from 0.45 mm and a flow length to wall thickness ratio up to 350. Injection pressures up to 2,200 bar and high melt throughputs up to 180 g/s can be attained. With its high process stability, this hot runner nozzle is also suitable for decorative injection molding using the IML process (In-mold Labeling).
- MTR-M nozzle offers advantages in the injection molding of polyesters to produce thick-walled parts with a high-gloss finish. When used for cosmetic packaging, household articles or in medical technology, wall thicknesses of 20 mm and more can be produced without problem.
- MTR-S type has also been developed for thick-walled parts with a wall thickness of up to 20 mm, but is geared specifically to the injection molding of Surlyn®, a crystal-clear ionomer from DuPont.
Reduced time-to-market for beverage and food capsules
Moreover with the explosive growth of single-serve beverage and food capsules, HRSflow Multitech and Plastic Technologies, Inc., a global leader in plastic package development, have partnered to provide brand owners with a turnkey commercialization pathway. The significant technical knowledge both companies have in this area will help improve speed-to-market and drive commercial success.
