Optimizing injection moulding operations with DMLS by EOS
EOS Additive Manufacturing allows direct integration of conformal cooling channels in moulds and mould inserts. Optimized heat dissipation enables shorter cycle times and increased productivity and plastic product quality in injection moulding operations.
In injection moulding, the cooling time of a finished product can constitute up to 70 per cent of the cycle time in series production. One reason: in conventional mould making, temperature control or cooling channels can only be drilled in a straight line. Critical hotspots often remain out of the coolant’s reach – and therefore cannot be mitigated.
Using Direct Metal Laser Sintering (DMLS) by EOS however makes it possible to integrate optimized, conformal cooling channels into the mould during the production process. This ensures faster and more even heat dissipation. It reduces thermal stress in the mould and prolongs service life. The plastic product quality and dimensional accuracy of the parts is also increased as well as reducing warpage. In addition, this also allows for a drastic reduction of cycle times.
LBC focuses on mould making using innovative laser technology, and adapts parts or the entire process chain to the customer’s operations. Using DMLS, the company was able to optimize the thermal performance of a mould insert. This reduced cycle time by 55 per cent from 90 to 40 sec., corresponding to a productivity increase of 125 per cent per annum. The 3,250 Euro investment was recouped within two months, and the company was able to save almost 20,000 euro per annum.
In another application, LBC was able to reduce cycle time by two-thirds, using a DMLS-manufactured core to ensure effective cooling of critical hotspots.
Es-Tec increased the mould productivity of a blow die with a build time of 50 hours by 20 per cent.
SIG Blowtech was able to lower cycle times from 15 to 9 sec. For a 4-bottle blow die with DMLS-manufactured inserts, the company now has achieved a 75 per cent increase in productivity.
EOS Additive Manufacturing technology – Injection moulding best-practice examples
Tooling: Innomia – Czech Tool Manufacturer Relies on Additive Manufacturing for Complex Customer Projects
Accelerate Production and Reduce Maintenance: Innomia uses EOS technology for optimizing manufacturing process for automotive components
The quality of plastic vehicle components has increased greatly over the last years: complexity, high fitting accuracy, visual appeal, and surface feel all meet the constant demand for premium quality – even in many of the high-priced models. Manufacturers and suppliers are relying more and more on high-tech solutions. One of the sectors in which the Czech Republic based company Innomia a.s. is active, is the automotive sector. The company has become a big advocate of the benefits of Direct Metal Laser Sintering (DMLS). Its portfolio spans prototype construction, the manufacture of inserts for injection molds and casting tools, tool repair and more.With the help of EOS technology, the DMLS professionals have supported the automotive supplier Magna in optimizing the production process for injection molded plastic parts. This involved a revision of the cooling process. The case concerns the manufacture of the arm-rest situated between the front seats.
The manufacture of the plastic components for the central arm-rest is undertaken by the supplier Magna – a customer of Innomia. Production is based on a classic injection molding process. This involves melted plastic filled with glass fibers, injected into the mold cavity and then solidifying. The component can be subsequently removed and is ready for delivery to the automotive manufacturer or to further suppliers in the chain. So much for the simplified version. In reality this is a complex process in which each step must function perfectly.
The heat energy of the liquid base material needs to be dissipated throughout the manufacturing tool to enable the plastic to solidify. The cooling process dictates, amongst other things, the quality of the component. This is because irregular heat dissipation can lead to deformations. Beyond that, temperature control plays a major role in dictating the production cycle time. The quicker the heat is removed, the sooner a component can be extracted and the next one produced.
The tool insert used to date has been made of extremely heat-conducting beryllium-copper alloy and cooling was only possible from one side of the insert. This meant that the temperature distribution was uneven. The cooling water needed to be very cold, just 16°C, in order to absorb the level of heat energy. Through the high insert surface temperatures – up to 120°C – the humidity rose in the vicinity, which, in turn, accelerated corrosion. This resulted in a cost intensive cleaning being necessary every one to two weeks. The hardness of the mold core was all that prevented damage of surfaces during the regular cleaning process.
As a logical consequence, the designers from Innomia began to develop a new tool insert cooling system. The optimized removal of heat generated in the production process was right at the top of the list of priorities. The team decided to go with integrated precision cooling channels, a tried and tested application under DMLS technology, and one of the solutions that only Additive Manufacturing processes can provide. The EOSINT M 270 system from EOS, a system proven over many years, was deployed for Innomia.
The diameter of the cooling channels is just 3 mm. The metal chosen was Maraging Steel 1.2709. The manufacturing process – the layered application and melting of the metal powder corresponding to 3D-data – enabled the employees of the Czech specialists to increase the degree of hardness through post-treatment to over 50 HRC. These mechanical characteristics guarantee a high resistance to wear and thereby reduce the maintenance costs.
“The DMLS process, using the EOSINT M 270, enabled us to manufacture an extremely durable component, while at the same time successfully retaining the proven advantages of the method in terms of design and reduced cycle times,” explains Luboš Rozkošný, CEO at Innomia. “Thanks to the cooling channels, integrated in the component with optimum precision, we have resolved the main challenge of the production process, and done so with limited expense.”
The precision cooling and the production using Additive Manufacturing technology has had the desired results. The temperature distribution and associated heat dissipation are now substantially more homogenized. Since the heat is distributed and leaves both the tool and the component quicker, a water temperature of 60°C is sufficient for cooling – reducing the energy needed. The insert surface itself does not heat up beyond 90°C, a fact that further allowed the engineers to resolve the humidity problems in the surrounding area.
Thanks to Innomia and EOS technology, Magna profits from a maintenance interval that is extended to between five and six weeks. The problem of air humidity condensation and potential cavity corrosion was solved completely. The uniform cooling channels are work so well that the time required for the production cycle is now 17% lower than before. As a result of the even and fast distribution and dissipation of heat, the components no longer deform. This has a direct and positive influence on the quality and speed of manufacturing. The reduction of the production cycle time and the improved quality of the end product are simultaneous benefits. After 370,000 cycles, Innomia and Magna have further improved the results. In this period the total savings have already reached some 20,000 euros.
Pavel Strnadek, Head of Tool Maintenance at Magna, is very happy with the results: “The issue of cooling was something that we’ve been trying to deal with for a long time. We knew how an improved product would have to look, but manufacturing it just wasn’t possible. Additive Manufacturing allowed us to make the breakthrough. We were able to plan the cooling channels just as we wanted them and then manufacture the mold core correspondingly. The laser fuses the metallic powder layer by layer, so that in effect any shape is possible. The result has convinced us at every level. Maintenance, quality of the end product, costs, heat dissipation – it’s been the perfect project.” Additive Manufacturing technologies are helping companies to deliver the promise of quality in automobile construction – Magna, a supplier to Škoda, demonstrates this on a daily basis.
“The automobile industry in Europe is subject to stiff competition. This fact naturally has an effect on suppliers such as Magna. That’s why it’s very important for us to be able to produce to the highest quality standards at the lowest price. With the optimization of our production plant via the improved cooling of our tools, we have created a textbook example of how technology can help increase efficiency. We reduced the maintenance costs for our production plant, optimized the quality of our components and increased the number of production cycles. This enabled us to uphold the promise of quality we made to our client and, at the same time, meet our own high demands regarding cost-effectiveness.”
INNOMIA a.s. was founded in 2006. The company’s goal is to support and advise customers such as Magna, the Škoda supplier, on the development and manufacture of products, and of metal and plastic prototypes.
Tooling: Salcomp – Additive Manufacturing Permits Optimized Cooling for Maximum Production Efficiency
EOS Technology helps to implement precise conformal cooling channels for increased production and less waste
According to the German industry association BITKOM, more than 700 mill. smartphones were sold worldwide in 2012 – an unbelieva
bly dynamic growth market and one in which, in addition to the large well-known manufacturers, the suppliers play a decisive role. Market leader Salcomp, based in Chennai, India, produces plugs and power supply units for cell phones. The company has additional market potential through the production of LED drivers. The total manufacturing capacity amounts to more than 440 mill. units per year. In the light of such large quantities, optimizing the production process becomes a crucial factor in a company’s ability to compete. For the construction of its production tools, Salcomp relies on the Additive Manufacturing technology provided by EOS.
As is the case in the mass production of comparable products, Salcomp usually produces the in-house parts by means of a plastic injection moulding process provided by their qualified supplier: The respective machine transports heat-liquefied plastic into a mould, known as the cavity. In the hardening process the part must cool in the shortest time possible. Immediately after-wards the machine releases the finished part. Thanks to state-of-the-art materials and ever more efficient manufacturing tools, the production process has been significantly shortened, while quality has also improved.
Further improvement to an already successful process is difficult. However, efficiency gains are a necessity when competing internationally. The key element of the production process which need to be improved is cooling. But this is also difficult element to improve: Even the fastest machines cannot increase production speed once the physical limitations of the base material have been reached, or when the relevant raw material costs cannot be reduced any further. The fact of the matter is that the temperature and the ability to cool rapidly play a decisive role in the manufacturing process.
Cooling channels are responsible for dissipating heat. These are situated all around the cavity. Under traditional production methods the scope for flexibility in the design of the cooling system was extremely limited: Because the tools themselves were either cast or turned from metal, the form specification was restricted by the possibility of drilling or hollowing out the corresponding moulds. It was not possible to produce curves and other complex shapes using such processes.
A change in the plastic proprietary production material was not an option, so Salcomp decided to seek new alternatives for the optimization of the cooling system. The aim was to construct the manufacturing tools in such a way that the parts could cool at a faster rate. As a consequence, the project managers decided to look more closely at the design of the cooling channels. Following this process, they looked into the possibility of perfecting the form and finding a technology capable of producing the corresponding structure.
The solution to the first part of the task was as follows: The cooling elements themselves were to be brought closer to the cavity. In this way, the heat from the layer of metal can pass through and exit the machine faster. At the same time, the fine points of the design should make sure that this evacuation takes place as effectively as possible. In order to bring the plan to fruition, Salcomp required a technology that made the precision positioning of the cooling channels possible, without causing any new problems.
Since drilling, turning, or other options could neither provide the necessary flexibility of design nor the required precision, Additive Manufacturing, in this case metal-based, entered the discussion: Salcomp commissioned a third party to utilize EOS technology in the producing EOSINT M 270, applying Direct Metal Laser Sintering (DMLS) for the manufacture of its core inserts. Simulation models were used in order to establish an ideal form for use in the production process.
The successful change to tool production had an effect: As planned the cooling channels were to be moved to the smallest possible distance from the edges of the core inserts, so they became conformal. At the same time, the quality of the end-product as a whole was improved thanks to the use of Additive Manufacturing. “The reason for this is the extreme precision that the process offers, in which a laser beam hardens the metal granulate, layer by layer, to exactly the specifications set down by the engineers using 3D software”, explains Krishnan Ramkumar, Tooling Specialist from EOS India, who was in charge of the project on site.
The improvements are now showing positive effects in the daily production run at Salcomp: The time required for cooling was reduced from 14 to just 8 sec for each production cycle. The company was able to increase its monthly output through this efficiency gain by more than 56,000 units, without having to make adjustments to their manufacturing machinery. The annual cost savings amount to 20,000 euros.
In addition, the reject rate fell from 2% to 1.4%, bringing cost savings and a reduction in the environmental impact of the production process. The final result is increased production quality, in spite of shortening the production cycle.
“We are extremely satisfied with the results achieved through our new, precision cooling design. Our core inserts, produced using Additive Manufacturing technology, are achieving the benefits that we were looking for: We were able to shorten the production cycle while simultaneously improving quality. The reduced costs combined with the increased rate of production have shown that technology is not simply self-serving but also has a positive impact on our business”, says Arumugam Narayanaswami, responsible for sourcing at Salcomp. “We are confident that in the future we will be able to identify further fields in which EOS technology can be utilized to increase our profitability.“
“The production process using Additive Manufacturing technology proved to be ideal. We were able to furnish the core inserts with optimally designed cooling channels. The heat was evacuated far quicker, cutting the production cycle from 14 to just 8 sec, and bringing about a 56,000 unit rise in monthly production.“
Arumugam Narayanaswami, Sourcing at Salcomp
Salcomp, who is a supplier to Nokia, offers mass production of power adapters, chargers and LED drivers. The total capacity of its production plants in Shenzhen (China), Chennai (India) and in Manaus (Brazil) is over 440 mill. pieces. The company delivers large volumes globally and provides worldwide service.