Economic LSR solutions for highly precise small parts

For Fakuma 2012, the babyplast product family presents energy-efficient solutions in 1K and 2K to increase the cost-effectiveness of injection molding small and micro parts. This time, the focus is on LSR components (Liquid Silicone Rubber), which can be used to upgrade or retrofit babyplast machines. The LSR table machines impress with clever application-specific solutions, especially where conventional injection molding machines with LSR dosing systems reach technical or economic limits.

Small, highly precise LSR micro-injection molded parts, used in medical, pharmaceutical, automotive, or telecommunications sectors, are currently trending. Until now, there were hardly any economical solutions on the market for these applications. Therefore, babyplast developed LSR components that perfectly leverage the known advantages of small injection molding machines. Initially designed for laboratory and development departments to produce pre-series and material tests, the first babyplast system solutions quickly established themselves in industrial serial production in 2012. At the debut at DKT 2012, the rubber industry was impressed by the unconventional, extremely compact solution from Kierspe. From the outset, over 20 systems have already been delivered across Europe. Fakuma 2012 allows a broad audience to get an impression of the niche LSR solutions.

Small but fine - LSR micro-injection molding in a completely different way

Genetically, babyplast solutions target areas where traditional solutions threaten to become uneconomical. This also applies to LSR processing: especially for demanding, precise micro and small parts, conventional injection molding solutions with multi-cavity technology reach technical or economic limits. Mainly due to minimum shot weights, but also shot weight consistency, and economically due to investment and operating costs. Not least, babyplast machines are highly flexible in manufacturing, especially when it comes to tool, material, or color changes.

Making LSR more economical

The advantages become particularly apparent in terms of energy efficiency: compared to a conventional injection molding machine (200 kN), the babyplast machine uses only about 20% of the energy required. It is also very small, with a footprint of approximately 0.8 m² (including LSR unit), and as a table machine, highly mobile in daily production. "We calculate a machine hourly rate at about 50% of conventional injection molding machines. That’s probably the benchmark for the low price," notes Marc Tesche, Technical Sales Manager at babyplast.

Short paths – faster and better LSR processing

One of the advantages of a babyplast LSR solution is its basic design. Compared to traditional LSR dosing units often equipped with barrel pumps and at least 20-liter containers, the compact design and short paths result in very low LSR volumes in lines and mixing chambers. The manufacturer estimates around 20% savings in this regard. "This effect significantly reduces material residence times, decreases material losses, and simplifies the time and cost effort during color or material changes," adds Marc Tesche. The already compact footprint is further enhanced by technical advantages of the machine.

Clever production benefits through two LSR variants

The new babyplast LSR modular system is available in two variants. One is a "LSR cartridge solution," primarily for shot weights up to about 1g. It uses a pre-mixed cartridge with 400 ml capacity. This solution is advantageous for very small, high-precision LSR parts. It allows easy and quick color changes and facilitates straightforward operation. Alternatively, the operator can choose a "larger" solution: an "LSR mixing and dosing unit" for shot weights greater than 1 gram. This includes a mixing and dosing unit with two cartridges of 1,000 ml each and a color dosing system, mounted on the babyplast injection molding machine. This LSR unit works with a maximum shot weight of about 18 g at a maximum operating pressure of 60 bar. The two cartridge holders have an air connection and a check valve. A pneumatic drive moves the stainless steel extrusion cylinder, which feeds the LSR material from the cartridge via a hose connection with an outlet valve. The LSR dosing and injection unit, as well as the pneumatically operated cold runner longitudinal needle valve for the tool, are water-cooled. Additionally, the machine features a vacuum pump for evacuating the tool, heating control units for temperature regulation, a filling device for cartridges, and a sprue removal device for ejecting small parts from the cavity.

High-end in a cleanroom

The LSR version of a babyplast machine can optionally be equipped with stainless steel body and protective enclosures for operation in gray or cleanroom environments. A laminar flow solution, as a cleanroom module above the tool area, can also be used if no enclosure is required. Whether for technical cleanrooms or high-quality systems in medical technology and pharmaceuticals – babyplast easily adapts to the higher requirements of GMP.

Retrofitting or upgrading as desired

The babyplast LSR modular system demonstrates high flexibility in both conversion and retrofitting: standard machines can be operated either with thermoplastic or LSR equipment. According to the manufacturer, converting from thermoplastics to LSR takes about 30 minutes. The special LSR software can be selected via the touch-screen control. Generally, all babyplast machines from the pT series can be retrofitted. Marc Tesche comments on the new development: "The babyplast LSR modular system offers all the known advantages of larger solutions. Added to that are the benefits of our somewhat different 'miniaturization philosophy' at babyplast. Size still counts in LSR processing, and it pays off. The processor now has a completely new approach to value creation and increased flexibility."

Image: Consciously different in the LSR niche: babyplast machine with LSR mixing and dosing unit