To put a figure on the cycle time reduction gained by cooling outside the mold, Bayer MaterialScience AG, Leverkusen, Germany, performed thermal simulations for a 20-mm-thick cuboidal part of polycarbonate (Fig. 5). Bayer specialists compared a one-layer process, a three-layer sandwich process, and a three-layer sandwich process with external intermediate cooling. The layer-thickness distribution was adapted to the process. In the three-layer sandwich process, the 4-mm-thick top layers required the same cooling time as the preform with 12-mm thickness. In a variant with external intermediate cooling, the preform was assumed to have a thickness of 12.8 mm and the top layers were 3.6 mm.

• Productivity is a suitable key indicator for an economic comparison, because it includes the assumption of equal numbers of cavities.

The productivity is therefore used for further assessment. It is defined as the ratio between the parts produced and the production factors necessary for this—in this case, the cavities. To obtain the relative productivity of multilayer molding compared with the single-layer method, equation 5 needs only to be divided by the number of cavities—i.e., by n in the case of overmolding on one side and by (n+1)/2 in the case of overmolding on both sides:

Say “manufacturing automation” and thoughts immediately go to the shop floor and specialized production equipment, robotics and material handling systems. But there is another realm of possible automation — the front office.

Along with the cycle time, the residence time of the material in the barrel and hot runner also decreases. That has the benefit of reduced yellowing and therefore greater light transmission. The maximum residence times recommended by the material manufacturers can be maintained.

Tests and simulations demonstrate that, for the manufacture of thick-walled parts with external intermediate cooling, the cooling time in the mold can be reduced by 25% to 50% compared with conventional multilayer molding, depending on the geometry of the part. At the K 2013 show in Düsseldorf, Engel—together with its project partners Bayer MaterialScience and the Krallmann Group (a German moldmaker)—demonstrated the potential of this process live for the first time. An optical lens from PC (Makrolon LED 2245) was molded in record time at the show.

Second quarter started with price hikes in PE and the four volume engineering resins, but relatively stable pricing was largely expected by the quarter’s end.

Processors with sustainability goals or mandates have a number of ways to reach their goals. Biopolymers are among them.

Across the show, sustainability ruled in new materials technology, from polyolefins and engineering resins to biobased materials.

While prices moved up for three of the five commodity resins, there was potential for a flat trajectory for the rest of the third quarter.

However, the cooling time or number of parts is only conditionally suitable as values for an efficiency comparison. These values do not take into account the fact that multilayer processes require a larger number of cavities. However, increased efficiency can be expected from larger numbers of cavities anyway. If with single-layer processes, for example, twice the number of cavities is available, the number of parts per unit time would also be twice as high.

Gifted with extraordinary technical know how and an authoritative yet plain English writing style, in this collection of articles Fattori offers his insights on a variety of molding-related topics that are bound to make your days on the production floor go a little bit better.

Second, it should be noted that only the layer manufactured first is cooled on both sides (layer 1 in Fig.1). The following layers only have contact with the mold wall on one side, while the preform borders on the other side, which, for the sake of simplicity, is regarded as an ideal insulator. To obtain the same cooling time in all stations, the following layers, which are cooled on one side, should be only half as thick as the first layer, which is cooled on both sides.

Sustainability continues to dominate new additives technology, but upping performance is also evident. Most of the new additives have been targeted to commodity resins and particularly polyolefins.

Approximation formulas for cooling time and molding productivity can be derived from theoretical considerations (see sidebar), and the results can be illustrated according to the number of layers (Fig.2). The technical literature, however, shows that this rule of thumb provides too optimistic results for estimating the cooling time saving with multilayer technology.

An exclusive event was held the evening before the opening celebration; the official portion followed on 7 June with Managing Partner Michael Hehl and Managing Director Technology & Engineering Guido Frohnhaus. In total, around 250 invited customers and partners used the opportunity to take in the new facilities. All seven ALLROUNDER machines were in operation, showcasing interesting applications to demonstrate the wide range of injection moulding products and services. The programme of events was rounded off with presentations on hot topics such as digitalisation, sustainability and hybrid machine technology.

While prices moved up for three of the five commodity resins, there was potential for a flat trajectory for the rest of the third quarter.

In this collection, which is part one of a series representing some of John’s finest work, we present you with five articles that we think you will refer to time and again as you look to solve problems, cut cycle times and improve the quality of the parts you mold.

Implementing a production monitoring system as the foundation of a ‘smart factory’ is about integrating people with new technology as much as it is about integrating machines and computers. Here are tips from a company that has gone through the process.

Mixed in among thought leaders from leading suppliers to injection molders and mold makers at the 2023 Molding and MoldMaking conferences will be molders and toolmakers themselves.

Previously we have discussed the effects of temperature and time on the long-term behavior of polymers. Now let's take a look at stress.

A new process therefore includes a cooling stage outside the mold between the injection shots. Cooling in air does take longer than in the mold but does not influence the cycle time. Depending on the duration of the external cooling, the

The sandwich option, consequently, has an advantage over overmolding on one side. This alternative also improves the contour accuracy, since sink marks in the preform due to shrinkage can be compensated by overmolding. Shrinkage of the thinner outer layers is thus responsible for the contour accuracy. This effect is also present for overmolding on one side, but of course only on one side. The quality of the other surface must therefore meet requirements immediately after molding, since it does not contain a corrective top layer. The opening photo shows the three-layer sandwich process in series production of LED headlamps at Automotive Lighting Reutlingen GmbH in Germany.

The number of parts T(n) per unit time corresponds to the reciprocal of the time per part—i.e., the reciprocal of the cycle time. Instead of the cycle time, the cooling time is used here, which is permissible to a first approximation for very thick-walled parts. From the reciprocal of equation 4, the relative number of parts is thus obtained:

Join this webinar to explore the transformative benefits of retrofitting your existing injection molding machines (IMMs). Engel will guide you through upgrading your equipment to enhance monitoring, control and adaptability — all while integrating digital technologies. You'll learn about the latest trends in IMM retrofitting (including Euromap interfaces and plasticizing retrofits) and discover how to future-proof your machines for a competitive edge. With insights from industry experts, it'll walk you through the decision-making process, ensuring you make informed choices that drive your business forward. Agenda: Maximize the value of your current IMMs through strategic retrofitting Learn how to integrate digital technologies to enhance monitoring and control Explore the benefits of Euromap interfaces and plasticizing retrofits Understand how retrofitting can help meet new product demands and improve adaptability Discover how Engel can support your retrofitting needs, from free consultations to execution

Join Engel in exploring the future of battery molding technology. Discover advancements in thermoplastic composites for battery housings, innovative automation solutions and the latest in large-tonnage equipment designed for e-mobility — all with a focus on cost-efficient solutions. Agenda: Learn about cutting-edge thermoplastic composites for durable, sustainable and cost-efficient battery housings Explore advanced automation concepts for efficient and scalable production See the latest large-tonnage equipment and technology innovations for e-mobility solutions

It is generally assumed that with a three-layer sandwich structure, the preform and the top layers must be cooled to below the glass-transition temperature at the end of the cooling time. However, tests have shown that the preform can be removed much earlier. It must only be ensured that its solidified outer layers are sufficiently strong to withstand the internal pressure and prevent deformation during demolding.

Mike Sepe has authored more than 25 ANTEC papers and more than 250 articles illustrating the importance of this interdisciplanary approach. In this collection, we present some of his best work during the years he has been contributing for Plastics Technology Magazine.

Resin drying is a crucial, but often-misunderstood area. This collection includes details on why and what you need to dry, how to specify a dryer, and best practices.

This month’s resin pricing report includes PT’s quarterly check-in on select engineering resins, including nylon 6 and 66.

technotrans says climate protection, energy efficiency and customization will be key discussion topics at PTXPO as it displays its protemp flow 6 ultrasonic eco and the teco cs 90t 9.1 TCUs.

• It is only with a large number of layers that overmolding on one side improves productivity to a significant extent. However, the productivity actually obtainable is affected by the times for mold opening, mold closing, mold transfer/rotation, and injection.

• For overmolding a preform on both sides, on the other hand, the productivity increases significantly starting with a three-layer structure.

For reliable performance, a slimline design and an unbeatable price, there is only one choice: the new ALLROUNDER 720 E GOLDEN ELECTRIC!

After successfully introducing a combined conference for moldmakers and injection molders in 2022, Plastics Technology and MoldMaking Technology are once again joining forces for a tooling/molding two-for-one.

Sequence of the process steps for conventional three-layer sandwich molding (top) and the variant with external intermediate cooling (bottom). The diagram shows schematically how, with external cooling, the different temperature at demolding of the preform (Tg: glass-transition temperature) and the different layer distribution significantly shorten the overall cooling time.

Additive technology creates air pockets in film during orientation, cutting down on the amount of resin needed while boosting opacity, mechanical properties and recyclability.

While the melting process does not provide perfect mixing, this study shows that mixing is indeed initiated during melting.

Shortly after the 40th anniversary celebrations, the ATC was cleared and gutted in August 2022. The comprehensive renovations and modernisations included installing photovoltaic and geothermal systems, a triple-glazed glass facade and efficient roof insulation. Following the renovation and thanks to the use of renewable energies, the annual primary energy requirement of the ATC Radevormwald is around just 40% of that of a newly built reference building. In addition, the top floor now accommodates redesigned training rooms with state-of-the-art presentation equipment. The technical centre also fulfils the latest requirements.

The aim of this presentation is to guide you through the factors and the numbers that will help you determine if a robot is a smart investment for your application. Agenda:  Why are you considering automation? What problems are you trying to solve? How and why automation can help Crunch the numbers and determine the ROI

The Plastics Industry Association (PLASTICS) has released final figures for NPE2024: The Plastics Show (May 6-10; Orlando) that officially make it the largest ever NPE in several key metrics.

The new process sequence is as follows: A preform for some cycles externally cooled to a predefined temperature is inserted into the mold again and overmolded. A new preform is then produced simultaneously or sequentially—depending on the number of injection units. After the opening of the mold, a finished part and a preform are removed and a preform that has previously been intermediately cooled is inserted again. The removed preform is deposited at a cooling station (Fig.3).

During overmolding on one side, n stations in the mold are necessary—i.e., as many stations as layers. In the sandwich variant, in which two layers lying one behind the other are produced simultaneously, as in a stacked mold, only (n+1)/2 stations are necessary. In this case, the number of layers n must be odd.

Join KraussMaffei for an insightful webinar designed for industry professionals, engineers and anyone interested in the manufacturing processes of PVC pipes. This session will provide a comprehensive understanding of the technology behind the production of high-quality PVC pipes: from raw material preparation to final product testing. Agenda: Introduction to PVC extrusion: overview of the basic principles of PVC pipe extrusion — including the process of melting and shaping PVC resin into pipe forms Equipment and machinery: detailed explanation of the key equipment involved — such as extruders, dies and cooling systems — and their roles in the extrusion process Process parameters: insight into the critical process parameters like temperature, pressure and cooling rates that influence the quality and consistency of the final PVC pipes Energy efficiency: examination of ways to save material and energy use when extruding PVC pipe products

Simulated cooling time per mold station and the calculated productivity (table below) for different manufacturing processes (material: PC). The single-layer part is used as a reference (100%) for comparison.

A new process therefore includes a cooling stage outside the mold between the injection shots. Cooling in air does take longer than in the mold but does not influence the cycle time. Depending on the duration of the external cooling, the preform can have a lower average temperature during overmolding than a preform in conventional sandwich technology. As a result, the preform absorbs more heat from the top layers and thereby reduces the cooling time. This effect can be further increased by making the preform thicker and the top layers thinner.

In a time where sustainability is no longer just a buzzword, the food and beverage packaging industry is required to be at the forefront of this innovation. By adopting circular packaging processes and solutions, producers can meet regulatory requirements while also satisfying consumer demand and enhancing brand reputation. Join Husky to learn more about the broader implications of the circular economy — as well as how leading brands are leveraging this opportunity to reduce costs, increase design flexibility and boost product differentiation. Agenda: The cost and operational benefits of embracing circularity Key materials in circular packaging — including rPET and emerging bioplastics How to design a circular food and beverage package Strategies for selecting sustainable closures to future-proof packaging solutions Optimization and streamlining of production processes for enhanced efficiency How Husky Technologies can enable your sustainable success

Despite price increase nominations going into second quarter, it appeared there was potential for generally flat pricing with the exception of a major downward correction for PP.

If the preform were immediately overmolded in the next station, no cycle-time reduction would be gained. On the contrary, the still hot inner regions of the preform would be further distanced from the mold wall and the cooling time would be extended.

Figure 6 shows the maximum temperature within the part during the cycle time. Whereas with the one-layer alternative, the highest temperature is always found in the core of the part, the location of the maximum changes for the two multilayer processes.

When, how, what and why to automate — leading robotics suppliers and forward-thinking moldmakers will share their insights on automating manufacturing at collocated event.

In this collection of articles, two of the industry’s foremost authorities on screw design — Jim Frankand and Mark Spalding — offer their sage advice on screw design...what works, what doesn’t, and what to look for when things start going wrong.

Discover how artifical intelligence is revolutionizing plastics processing. Hear from industry experts on the future impact of AI on your operations and envision a fully interconnected plant.

The criterion for calculating the cooling time of the end part is that all regions of the part must be cooled to below the glass-transition temperature of 150 C. In the alternative with external intermediate cooling, the preform is removed at a time when a 2.4-mm-thick, solidified outer layer has formed, but the core temperature is still 220 C. With this new process, the total cooling time in the mold can be cut in half. Since the number of required cavities is the same as with the known sandwich process, the productivity increases by the same factor by which the cooling time decreases.

Join Wittmann for an engaging webinar on the transformative impact of manufacturing execution systems (MES) in the plastic injection molding industry. Discover how MES enhances production efficiency, quality control and real-time monitoring while also reducing downtime. It will explore the integration of MES with existing systems, emphasizing compliance and traceability for automotive and medical sectors. Learn about the latest advancements in IoT and AI technologies and how they drive innovation and continuous improvement in MES. Agenda: Overview of MES benefits What is MES? Definition, role and brief history Historical perspective and evolution Longevity and analytics Connectivity: importance, standards and integration Advantages of MES: efficiency, real-time data, traceability and cost savings Emerging technologies: IoT and AI in MES

Introduced by Zeiger and Spark Industries at the PTXPO, the nozzle is designed for maximum heat transfer and uniformity with a continuous taper for self cleaning.

The cooling time is proportional to the square of the wall thickness. The cooling time te(n) of the first layer (which is cooled on both sides), corresponding to the cooling time tf(n) of all further layers (which are cooled on one side), is described by the following equation:

Simulated temperature within the part vs. time for a single-layer process (top), a three-layer sandwich process (center), and the new three-layer sandwich process with external intermediate cooling. (Melt temperature: 280 C; mold temperature for outer layers and single-layer variant: 120 C; mold temperature for inner layers: 70 C). The graphics also include the temperature distribution in the part interior after 164 sec. (Source: Bayer MaterialScience)

A new approach to multilayer injection molding boosts productivity in making challenging optical plastic parts, such as thick-walled LED lenses for automotive headlights, which have tolerances in the micron range.

Plastics Technology’s Tech Days is back! Every Tuesday in October, a series of five online presentations will be given by industry supplier around the following topics:  Injection Molding — New Technologies, Efficiencies Film Extrusion — New Technologies, Efficiencies Upstream/Downstream Operations Injection Molding — Sustainability Extrusion — Compounding Coming out of NPE2024, PT identified a variety of topics, technologies and trends that are driving and shaping the evolution of plastic products manufacturing — from recycling/recyclability and energy optimization to AI-based process control and automation implementation. PT Tech Days is designed to provide a robust, curated, accessible platform through which plastics professionals can explore these trends, have direct access to subject-matter experts and develop strategies for applying solutions in their operations.

Two assumptions are made: Firstly, known mold concepts (index plate, rotary table, sliding table) are used. Ideally, another preform is manufactured simultaneously with the overmolding of one preform. From this the requirement, known from multicomponent injection molding, it follows that the cooling times of all layers must be the same.

The rapid solidification rate of polycarbonate is beneficial for short cycle times. Simulations for acrylic (PMMA) with adjusted melt and mold temperatures generated a total cooling time of 314 sec, or almost twice as long. Figure 6 compares the cycle times and productivity of the three processes for the processing of polycarbonate.

Dipl.-Ing. Josef Giessauf is head of the process technology development department at Engel Austria. Contact: josef.giessauf@engel.at.

August 29-30 in Minneapolis all things injection molding and moldmaking will be happening at the Hyatt Regency — check out who’s speaking on what topics today.

Across all process types, sustainability was a big theme at NPE2024. But there was plenty to see in automation and artificial intelligence as well.

Both overmolding methods can offer a number of benefits. Cold-runner sprues or thin-walled exterior regions limit the possible maximum holding-pressure time. With very thick-walled parts, the sink marks can thus only be counteracted by increasing the holding pressure. This in turn requires machines with relatively high clamping forces. Extreme wall-thickness ratios can, in some cases, only be achieved through multilayer molding. The result is a gain in design freedom.

Mold maintenance is critical, and with this collection of content we’ve bundled some of the very best advice we’ve published on repairing, maintaining, evaluating and even hanging molds on injection molding machines.

Overmolding on two sides, versus on one side, does not at first offer a cooling-time reduction, but it provides the advantage of the stack mold—i.e., a saving of platen area and clamping force.

It has been explained above, and it can be seen in the sidebar, how multilayer molding can increase the profitability of production of thick-walled parts. It takes advantage of the fact that several thin layers will cool more rapidly than one thick layer. This can increase productivity by approximately a factor of two. However, the resulting cooling times of several minutes are still comparatively long for injection molding.

ABOUT THE AUTHORS: Christian Maier M.Sc. is project head in the process technology development department at Engel Austria GmbH, Schwertberg, Austria. Contact: christian.maier@engel.at.

Possible layer sequences for a thick-walled, three-layer lens. Left: Preform 1 one-side overmolded with layers 2 and 3 sequentially. Center: Preform 1 simultaneously overmolded on both sides with layers 2 and 2’ (sandwich variant). Right: Preforms 1 and 1’ connected by injection of a second layer 2 (Figure: Engel)

Benefit from our expertise and lower the costs for your injection moulding production by optimising your energy requirement.

Exhibitors and presenters at the plastics show emphasized 3D printing as a complement and aid to more traditional production processes.

While the major correction in PP prices was finally underway, generally stable pricing was anticipated for the other four commodity resins.

In molding thick optical lenses, what layer sequence is most appropriate, how many layers are necessary, and what savings potential can be expected? These questions can be answered with a few considerations that apply to one-sided and two-sided overmolding, but not to the bonding of two preforms (Fig.1). Since in the latter case, the heat removal from the connecting layers follows relatively complex laws, that alternative will not be considered.

Cooling time per station in the mold, depending on the number of layers as per equation 4 (see sidebar), and productivity as per equations 6 and 7. The respective single-layer part serves as a reference (100%) for comparing the illustrated results for overmolding on one side and on both sides.

Learn about sustainable scrap reprocessing—this resource offers a deep dive into everything from granulator types and options, to service tips, videos and technical articles.

• For the cooling time per cavity, it is unimportant whether overmolding is performed on one or both sides. In both cases the cooling time is reduced to the same degree as the number of layers increases.

This Knowledge Center provides an overview of the considerations needed to understand the purchase, operation, and maintenance of a process cooling system.

Multiple speakers at Molding 2023 will address the ways simulation can impact material substitution decisions, process profitability and simplification of mold design.

Thousands of people visit our Supplier Guide every day to source equipment and materials. Get in front of them with a free company profile.

The refurbished ARBURG Technology Center (ATC) in Radevormwald is back in operation. After a two-year modernisation phase, on 7 June 2024, ARBURG Partners Juliane and Michael Hehl, together with the Managing Directors and project leads, cut the reopening ribbon. This event, marked by an open house, followed an exclusive event the previous evening. The two-day event was attended by a total of around 250 guests.

Formnext Chicago is an industrial additive manufacturing expo taking place April 8-10, 2025 at McCormick Place in Chicago, Illinois. Formnext Chicago is the second in a series of Formnext events in the U.S. being produced by Mesago Messe Frankfurt, AMT – The Association For Manufacturing Technology, and Gardner Business Media (our publisher).

In this three-part collection, veteran molder and moldmaker Jim Fattori brings to bear his 40+ years of on-the-job experience and provides molders his “from the trenches” perspective on on the why, where and how of venting injection molds. Take the trial-and-error out of the molding venting process.

In general, individual layers are all produced on the same injection molding machine. The use of separate injection units for the three layers is already a first step towards short cycle times. This ensures that the process steps of injection, holding pressure, and metering take place simultaneously and independently of one another.

During the two-year transition period, the ARBURG staff in Radevormwald did everything possible to continue to offer customers the best support, with total dedication and flexibility. The team of thirty plus were based in an office building around a kilometre away. At the temporary location, the office work and customer service hotline were able to continue 100% in house. The good, long-standing relationships with customers proved to be an advantage. For application technology and training, the ARBURG staff was able to use the customers' machines on site.

Plastics Technology covers technical and business Information for Plastics Processors in Injection Molding, Extrusion, Blow Molding, Plastic Additives, Compounding, Plastic Materials, and Resin Pricing. About Us

Yet multilayer molding offers the possibility of maintaining the mold regions for those surfaces that subsequently have to be overmolded at a lower temperature, since, in an ideal case, the surface quality of the internal layers does not affect the quality of the lens that is produced. If this potential is used for the manufacture of the preform, the estimated cooling-time reduction agrees well with simulated and practical results. For optimizing the layer thickness distribution, it is advisable to carry out simulations.

Take a deep dive into all of the various aspects of part quoting to ensure you’ve got all the bases—as in costs—covered before preparing your customer’s quote for services.

Successfully starting or restarting an injection molding machine is less about ticking boxes on a rote checklist and more about individually assessing each processing scenario and its unique variables.

In Europe, the main focus of development for plastic optical parts is on thicker lenses for LED lights. Since the cooling time during injection molding increases with the square of the wall thickness, the biggest challenge is to develop economic processes for such lenses. With a typical thickness of 30 mm for automotive headlamps, cycle times of at least 20 min are to be expected with standard injection molding processes.

If the preform were immediately overmolded in the next station, no cycle-time reduction would be gained. On the contrary, the still hot inner regions of the preform would be further distanced from the mold wall and the cooling time would be extended.

Despite all the advantages of the sandwich alternative, it must not be overlooked that it requires a more complex mold technology. Retaining the preform in the cavity and transporting it from one cavity to another is challenging, while just a rotary table is sufficient for one-sided overmolding. Also, the simultaneous filling of the outer layers in two-sided overmolding must be well balanced—pressure differences between the top and bottom layers can cause the preform to fracture.

Core Technology Molding turned to Mold-Masters E-Multi auxiliary injection unit to help it win a job and dramatically change its process.

Baystar's Borstar technology is helping customers deliver better, more reliable production methods to greenhouse agriculture.

Prof. Dr.-Ing. Georg Steinbichler is senior v.p. of development technologies at Engel Austria and director of the Institute of Polymer-Injection Molding Technology and Process Automation at Johannes Kepler University in Linz, Austria. Contact: georg.steinbichler@engel.at

• Overmolding on one side requires a larger number of cavities, and therefore more space in the mold, compared with overmolding on both sides.

LED headlamp of the Mercedes S Class 2013 is produced by three-layer sandwich molding on an Engel duo 600 WP pico combi injection machine. (Photo: Automotive Lighting Reutlingen GmbH).

Improvements in nozzle design in recent years overcome some of the limitations of previous filter, mixing, and shut-off nozzles.

the glass-transition temperature at the end of the cooling time. However, tests have shown that the preform can be removed much earlier. It must only be ensured that its solidified outer layers are sufficiently strong to withstand the internal pressure and prevent deformation during demolding.

The arburgXworld customer portal gives you access to a wide range of digital apps and features that make your daily work easier.

In this collection of content, we provide expert advice on welding from some of the leading authorities in the field, with tips on such matters as controls, as well as insights on how to solve common problems in welding.

One possibility for cycle-time reduction is multilayer technology, in which the thick-walled parts are built up from multiple successive layers. The multilayer structure can be generated by overmolding a first layer on either one or both sides, or by subsequently bonding together two previously independent layers by means of an interlayer (Fig.1).

On the assumption that the first layer of a part produced from n layers is only half as thick as all the following layers, the layer thicknesses se of the first layer and sf of the following layers are as stated below, where stotal describes the total thickness of the part:

Ultradent's entry of its Umbrella cheek retractor took home the awards for Technical Sophistication and Achievement in Economics and Efficiency at PTXPO.