Category Archives: Molding

Mold Design: Virtually Optimized Cooling Channels

The thermal layout of a mold can be optimized during the design stage, understanding the effect of the cooling channel size and location over the part deformation and its solidification. With Sigmasoft Virtual Molding, which works as a virtual injection molding machine, it is possible to try different concepts and to evaluate the advantage of more expensive approaches, such as conformal cooling, before even starting to cut the steel.

Above: conventional cooling approach and resulting temperature distribution in the mold cavity. Below: conformal cooling approach (courtesy of IPC) and improved temperature distribution.

Thermal mold design is one of the most critical parameters determining the performance of an injection molding operation. Up to now, a lot was left to guessing and prior experiences. This approach is changing with the latest simulation tools, and one of the pioneers has been IPC, Innovation Plasturgie Composites, from Oyonnax, France, who has successfully used Sigmasoft Virtual Molding for six years in the design of their injection molds’ thermal layout.

IPC’s approach has been to carefully analyze the impact of different cooling concepts virtually to find the one that best suits their requirements. The company combines traditional cooling systems with conformal cooling. The analysis performed with Sigmasoft Virtual Molding allows them to quickly detect the impact of every iteration on the mold performance (in terms of cycle time) and on the part quality (regarding warpage and residual stresses).

“Using Sigmasoft Virtual Molding has helped us to be more reliable in the design phase”, states Eric Pauze, Design Manager and Responsible for the Business Unit Conception and Simulation. “IPC has been working on cooling optimization with conformal cooling in ALM in the tools for ten years. We are sensitive to thermal homogeneity of injected parts as a quality criteria check. Each system is designed and then tested using Sigmasoft to qualify the cooling benefit compared to standard systems. Through this software, we had also generated hours saving thanks to the preprocessor efficiency.”

Sigmasoft Virtual Molding follows a unique approach. It works like a virtual injection molding machine, reproducing precisely all the effects seen in reality. The mold, with all its components, is defined in the simulation. Each component is defined with its own material properties. Also the injection molding process is thoroughly set-up, just as in reality. Not only the injection, packing and solidification stages are considered, but also the dead times between processes, which are relevant in the heat transfer of the complete molding cycle.

The part deformation and its solidification behavior are a combination of all factors affecting the thermal mold performance. The thermal layout of the cooling channels is one of these factors. If there is a hot spot in the mold, either due to a very large concentration of plastic material over the part, or due to insufficient mold cooling, the part will shrink more in this area, affecting the overall warpage. A hot spot will also delay the solidification of the part.

In the example seen in Figure , a conventional cooling is considered for a plastic part. The cavity temperature distribution is seen on the right side. Below, the part is optimized with a cooling concept provided by IPC. As seen, the mold temperature is substantially reduced, and the cycle time can be decreased by around 27%.

Sigma Engineering GmbH presents its Virtual Molding technology at the upcoming FIP Solution Plastique trade show at booth M14. The show takes place between 13th and 16th June 2017 in Lyon, France.

Sigmasoft® reduces trial-and-error and pushes innovative processes

Sigma Engineering exhibits for the first time with their own booth at MECSPE in Parma, Italy. It takes this opportunity to introduce its Sigmasoft® Virtual Molding technology to a broad public and to widen its activities in the Italian market. The technology helps to optimize existing injection molding tools and processes as well as to virtually test innovative processing and tooling concepts.

Fig: The mold and complete process for the 2-component LSR egg cup were calculated upfront in Sigmasoft®  

Finding Ideal Set-Ups and Innovative Concepts
Between March 23rd and 25th, 2017, Sigma Engineering GmbH from Aachen, Germany, showcases its Sigmasoft® Virtual Molding technology at MECSPE, Parma. In Pad.6 at booth B50 the interested public has the opportunity to learn more about how Sigmasoft® supports the complete process development of injection molding processes. From the first design over the evaluation of different tooling concepts up to the ideal process set up on the machine, the simulation software helps its users to find the ideal solution. As Sigmasoft® works as a virtual injection molding machine different set-ups or new concepts are tested risk free on the computer. Thus, molders not only skip time and cost intensive trial-and-error on the machine, but also save resources and make their processes more profitable.

By reference to different practical examples, typical questions of elastomer, thermoplast, thermoset and Powder Injection Molding processes are answered by the Sigma team. Moreover the examples help to visualize the software’s potential for the visitors, especially in the fields of design, mold making and part production.

However, Sigmasoft® not only supports the optimization and improvement of classical injection molding processes, it also allows its users to safely try innovative processing and tooling concepts. The two-component egg cup, also an example from K show, highlights these possibilities for LSR applications. With Elmet Elastomere Produktions- und Dienstleistungs-GmbH and Momentive Performance Materials Inc., Sigma helped to realize a LSR on LSR application with an existing 1-component machine by the help of an adaptable unit. With Sigmasoft® Virtual Molding the practicability of different combinations of material, mold, machine and process was safely tested on the computer until the optimum solution was found.

Collaboration with MESGO
To improve the simulation results and to provide a wide variety of materials in their database, Sigma always seeks strong partnerships with material suppliers. One of these partners is the well-established compounder Mesgo group. To even further aid their customers during the development of new processes they measured three of their most popular silicone rubber compounds to make them available for a Sigmasoft® Virtual Molding analysis. With the next major release of Sigmasoft® its database will include one fluoro-silicone rubber and two silicone rubber compounds.

Production of aspherical mirrors for head-up displays (HUDs)

In November 2016, Arburg delivered the tenth Allrounder to Continental for the production of aspherical mirrors for head-up displays (HUDs). The company has been cooperating with Arburg on an exclusive basis in this highly demanding segment since 2010, for which it solely uses specially equipped electric machines from the Alldrive series. Demand for head-up displays is growing steadily: annual production increased by 70 percent to around 600,000 parts between 2015 and 2016 alone. There is no end in sight for this growth.

Head-up displays from Continental are installed in cars of various brands throughout the world. These use aspherical mirrors to project all driving-related information (such as the current road speed) onto the windscreen, and thus directly into the driver’s line of vision – an important contribution towards greater driver safety. Displaying this information on the screen without distortion requires moulds with accurate contours and high-precision surfaces. When producing the mirrors, it is essential to accurately reproduce the different curvatures of a wide variety of car windscreens.

Technological cooperation since 2010
Continental has been using Allrounders in plastics processing since 1970. In 2010, cooperation intensified in the field of head-up displays, as the production of aspherical mirrors makes extremely stringent demands in terms of precision. In the case of the injected part, the permissible deviation from the target geometry is less than five micrometres, in other words the diameter of a human hair.
Accordingly, technological cooperation between the two companies covers not only machine design, but also joint process optimisation in terms of sequencing and programming.

Specially equipped ALLROUNDERs
In order to mould the mirrors from Cycloolefin-Copolymer (COC), a special transparent thermoplastic, the electric Allrounders of the Alldrive machine series feature injection compression moulding equipment. A sensor in the mould detects the coining gap and the internal mould pressure during injection compression moulding. The Selogica machine control system monitors these measurement signals. Near-contour temperature control is implemented in up to twelve individual mould temperature control zones. The sprue is removed immediately in the mould. After the injection moulding process, a six-axis robot with specially adapted gripper removes the mirrors without bending them and transfers them to a laser station. Here, each part is marked with its own individual production data, so that it can be identified directly and tracked through production. This step is in line with the requirements of Industry 4.0. Next, the mirrors are set down onto a cooling station, where they are cooled from below with ionised air. This is followed by 100 percent measurement and vacuum deposition of highly-reflective aluminium on the front side. The whole process, including packaging, is fully automated and takes place in a clean-room. This reliably prevents contamination from dust particles.

Continuous advances in development
Continental is now producing its third generation of head-up displays. While the first-generation moulded parts still required downstream assembly operations, the optical and mechanical functions are now directly integrated in the current versions. They can be installed directly in the housing, which enhances production efficiency. HUD development is moving in the direction of larger mirrors, better image quality, integration of assist systems and augmented reality applications.

World PM2016: Arburg to showcase trends in powder injection moulding

At the “World PM2016 Congress and Exhibition” to be held from 9 to 13 October in Hamburg, Germany, Arburg will demonstrate the cost-efficient production of smartphone housings. The innovative powder injection moulding application implemented jointly with partner BASF, which will be shown on a hydraulic Allrounder 470 S, is a production-efficient and cost-effective alternative to conventional machining processes.

HyperFocal: 0

“The booming international smartphone market offers huge potential for powder injection moulding,” says Arburg PIM expert Hartmut Walcher. “We’re receiving more and more inquiries from this segment at international trade fairs. As a result, we’ve now established a joint venture with BASF for an innovative PIM application that will be seen for the first time at the World PM2016 fair. This enables significant cost savings in comparison with conventional machining processes.”

Exhibition: innovative smartphone application
A hydraulic Allrounder 470 S with a clamping force of 1,100 kN and PIM equipment will produce back housings for smartphones in Hamburg. Catamold 17-4 PH Plus from BASF is used as the feedstock. In addition to the back housing, the changeable hot-runner mould featuring liquid temperature control is also designed to produce a closed or four-part frame for smartphone housings.
At the World PM2016 trade fair, a green compact for a smartphone back housing in an Arburg design will be produced in a cycle time of around one minute. In order to minimise part distortion at a wall thickness of only around one millimetre, the mould temperature is dynamically controlled in the subsequent sintering process to ensure a constant green density throughout the entire part. The reason for dynamic mould temperature control is the significantly higher thermal conductivity of the feedstock compared to thermoplastics. A linear Multilift Select robotic system gently removes the moulded green compacts and sets them down on a slide rail.

Congress: presentation on quality optimisation
Christian Knöpfle, Application Technology Consultant at Arburg, will speak on the results of his scientific investigations into the quality optimisation of MIM parts at the Congress accompanying the trade fair on 10 October 2016 (“Technical Session 5”, 2:00 to 3:40 p.m.). The presentation will cover the effects of the process parameters injection speed, holding pressure, mould temperature, cavity evacuation and gate geometry on the quality of MIM parts.

Arburg: More than 50 years of PIM experience
Injection moulding machine manufacturer Arburg has more than 50 years of experience in powder injection moulding and has produced far in excess of 1,000 PIM machines for a broad range of applications and industries, including the automotive, jewellery and watch industries, as well as the IT and dental sectors. The company’s expertise ranges from feedstock preparation and the complex manufacturing of micro-PIM parts through to cost-effective component assembly integration and the design and implementation of complete turnkey systems. In addition, in addition to injection moulding, all upstream and downstream production steps such as material preparation, debinding, sintering and part analyses can also be tested under practical conditions at its in-house PIM laboratory.

Hands-on Virtual Molding

At the world plastics show K 2016, from October 19th to 26th, SIGMA Engineering GmbH surprises visitors with an entirely new perspective on its SIGMASOFT Virtual Molding technology. Under the motto “Hands-on Virtual Molding” the usage along the complete development chain is highlighted – from part design, over mold manufacturing up to serial production. SIGMA furthermore offers a first outlook on future software developments, which include DOE (Design of Experiments) and an optimization tool.

Sans titre

To make the software potential visible to users, the fields of design, mold making and part production occupy center stage. The possible applications and technical challenges within these areas are demonstrated through practical examples. Amongst them is the bottle carrier mesh “Ursula” by CVA Silicone, which is presented in collaboration with the companies Momentive Performance Materials, CVA Silicone and Engel at the SIGMA booth. Visitors thus experience first-hand the consistency of reality and SIGMASOFT Virtual Molding.

In another exhibit visitors also have the chance to experience virtual and real production: Momentive demonstrates in hall 6 at booth B15 their Silopren* LSR 2670 for a 2K-application in a 4+4-cavity mold from ELMET. The two component part of LSR on LSR is realized with just one dosing pump on an Arburg Allrounder 470 A. The virtual production to design the process is presented by SIGMA at its own booth.

Examples from thermoplastic processing are also on view. SIGMA shows, amongst other cases, the potential of Virtual Molding to optimize warpage and deformation in technical parts together with F. & G. Hachtel. Visitors moreover have the possibility to discuss their own questions with the SIGMA engineers.

Taipei Plas 2016: “Golden” Allrounder for efficient plastic processing

From 12 to 16 August, Arburg will be presenting an electric and a hydraulic injection moulding machine at the Taipei Plas 2016 in Taiwan. An Allrounder 470 E Golden Electric machine of the electric entry-level series will produce pill splitters for the medical technology sector. A flexible smartphone bumper will be made from liquid silicone (LSR) on a hydraulic Allrounder. On both automated applications, part handling is performed via a linear Multilift Select robotic system.

570 E, 370 E, EDRIVE, Perspektive
570 E, 370 E, EDRIVE, Perspektive

“The Taipei Plas represents an excellent opportunity to present our team to our customers in Taiwan and to demonstrate the latest technologies and industrial applications,” says Michael Huang, Managing Director of the Arburg subsidiary in Taiwan, which was newly established in April 2016. “With the new electric Golden Electric machine series, we are continuing the success story of the hydraulic Allrounder Golden Edition. Both meet the requirements of high-performance entry-level machines for the precise and production-efficient manufacture of complex moulded parts. Beyond first-class machine technology, we also offer expert technical support – from project planning through to optimisation of the production processes and service.”

New Golden Electric machine series
The injection moulding machines of the new Golden Electric series impress with high-quality, proven Arburg technology “Made in Germany” at an attractive price/performance ratio. This is made possible through standardised components such as fixed combinations of distance between tie bars, clamping force and injection unit size. The Allrounder Golden Electric is available in the four machine sizes 370, 470, 520 and 570 with clamping forces of 600, 1,000, 1,500 and 2,000 kN. In Taipei, an Allrounder 470 E Golden Electric machine with a clamping force of 1,000 kN and a size 290 injection unit will produce pill splitters for the medical technology sector. For this purpose, four blades are inserted into the 4+4-cavity mould and overmoulded, while the upper section of the splitter is simultaneously produced from PC. The cycle time is around 25 seconds and the moulded part weight is 22 grams. Removal and assembly of the upper and lower sections is performed by a linear Multilift Select robotic system.

Technical injection moulding: Smartphone bumpers from LSR
At the Taipei Plas 2016, an hydraulic Allrounder, also with a clamping force of 1,000 kN and a size 290 injection unit, will be presented. The machine is designed for the processing of liquid silicone (LSR) and produces flexible LSR bumpers for the iPhone 6 in a cycle time of around 20 seconds. The part weight is 21 grams. The mould is supplied by Prover, the LSR dosage system by 2 KM. Handling is performed by a Multilift Select robotic system with a load-bearing capacity of 6 kilograms.
The Multilift Select is the entry-level model among the linear robotic systems from Arburg. It features servo-electric drive axes and is fully integrated in the Selogica machine control system. For the user, this means: only one data record, familiar approach during programming and perfect synchronisation of robotic system and machine. Moreover, the Multilift Select is extremely simple to program thanks to the teach-in function.

New Arburg subsidiary in Taiwan
Under the direction of Michael Huang, the Arburg subsidiary in Taiwan officially began operating in April 2016. The new location in Taichung is an important milestone for the further expansion of the global network and the activities in Asia. Arburg was previously represented by a trading partner in Taiwan since 1981. By taking on many of the Sales and Service employees from this partner, the customers can continue to benefit from the well-founded knowledge available and their familiar local contacts. The showroom offers space for three Allrounders, training rooms and a well-stocked spare parts store. The infrastructure in Taiwan will be expanded in a targeted manner, for example through wide-ranging service offerings and application technology consulting.

Mastering the Challenges in LSR Molding

Products made of LSR (Liquid Silicon Rubber) confront the molder with special challenges. Due to its rheological properties and curing kinetics, the desired quality outcome can only be achieved through a narrow process window.


However, LSR has good physiological properties and a high thermal stability and has therefore a growing demand, particularly in the medical, baby care and design sectors.
To face the challenging production with sufficient preparation, the narrow processing window can be set up upfront with SIGMASOFT® Virtual Molding. This way the processor increases his know-how for future projects, and also the process stability. The risks associated with costs and delivery dates are also reduced.

The advantages of a virtual injection molding process are shown by SIGMA Engineering GmbH at Fakuma 2015 in a joint project with Momentive Performance Materials Inc. and CVA Sillicone. For this purpose, the design article “Ursula”, a carry-mesh for bottles, is evaluated with SIGMASOFT® Virtual Molding. The interlaced geometry of “Ursula” with a maximum flow-length of 619 mm requires stable flow and curing properties, to guarantee a robust process and the required part quality.

To reach this goal, the manufacturing feasibility was evaluated with SIGMASOFT® Virtual Molding. Not only the part, but the complete mold was taken into account, including cold runner, over several molding cycles. Besides the filling of the mold (Figure) and the part curing behavior, also the complete thermal mold behavior was considered. The thermal response of the mold has a decisive impact on the part properties. The comprehensive rheological and thermal analysis shows that the Silopren LSR 2670 meets the production requirements of Ursula. The results of the virtual production are shown at Fakuma at the SIGMA Booth, A5-5105. A Live-Demo is presented at the booth of Momentive (A4-4307), where Ursula will be produced in a CVA mold.

To achieve an accurate prediction with SIGMASOFT®, besides the complete mold and process data, it is important to have precise material data, to calculate exactly the material behavior. To make those easier accessible for SIGMASOFT® users, Momentive delivers the material data of a large number of its materials to SIGMA. The new material data for several standard and special LSR grades are available for the user in the SIGMASOFT® v5.1 database.