Heißkanaldüsen Typ SLT/-DLT Customer information

More documents

Recommendations

Info

Heißkanaldüsen Customer information Typ SLT/-DLT Vliesolen – Bamboo Fibre Reinforced Plastics The firm of PMG Geotex in Chemnitz compounds plastics with exotic filling materials. Instead of the usual glass fibres special, they use bamboo fibres to modify the properties of polypropylene or polyethylene, for example. Depending on their length, the bamboo fibres can be used in different areas. For example, longer fibres are mixed into screed or concrete to prevent cracks forming during drying. The shorter bamboo fibres are compounded into plastics as reinforcement or filling material.These fibres, which are chemically linked with the polymer, make the plastics much stronger than those that are not reinforced. In addition this filling material also has an impact on the price of the product. The properties of a PP modified with 30% bamboo fibres rank between unreinforced polypropylene and polypropylene that is reinforced with approx. 20% glass fibre. There is no problem in processing these plastics conventionally with cold runners. However, more and more interested parties ask about the possibility of processing this material with hot runners too. The trials carried out by PMG and GÜNTHER Heisskanaltechnik GmbH together show that it is possible to process plastics filled with bamboo fibres with hot runners also. Three plastics (PP, PE–LD /PE-HD), each with 30% bamboo fibres, were available for the processing trial: - Vliesolen BF30, natural (PP-2/30-HM1) - Vliesolen BF30, black (LDPE-2/30-HS2) - Vliesolen BF30 (HDPE-1/30-HM1) These materials were tested in a test mould (2-cavity: 1-gr washer), which was equipped alternatively with - nozzles of tip (5SHT50S) or - valve gate nozzles (5NHT50LA Small sprue gates are not suitable because the bamboo fibres are longer than glass fibres and there is a risk of the sprue gate getting clogged up with fibres. If the injection gate diameter is 1.6 mm (5SHT50) or 1.4 mm (5NHT50LA), the above types of materials can be processed without restriction. www.guenther-hotrunner.com 7/12 Subject to technical changes The hot runner nozzles used in the test feature a two-part shaft in the front area of the nozzle. This structural feature provides excellent thermal isolation between the hot runner nozzle and the mold. This thermal separation also has a positive effect on the temperature control inside the nozzle. The hot runner nozzles are suitable for processing standard, engineering and high temperature plastics. When processing filled plastics, nozzle tips made of a hard metal alloy with good heat conductive properties provide very good wear protection. Material tube (25 W/mK) Heater Air (0,04 W/mK) Gap solidified plastic (0,2...1,2 W/mK) iA Fig. Standard hot-runner nozzle 5SHT50 with two-component shaft (patented). Nozzle with excellent insulation in the front shaft area. Picture: The two-stage shaft of the SHT type nozzle and the frozen plastic material which forms a "cap" around the nozzle provide for optimized isolation towards the cavity and therefore produce a homogeneous temperature profile in the nozzle. Valve gate nozzles can be recommended to achieve flash-free gate quality of the part. These nozzles are characterized by a long lifetime and short cycle times in operation. Melt Shaft made of titanium alloy (7 W/mK) Open nozzle tip (100 W/mK) For any questions, please contact our Application Engineering department at + 49 (0) 6451 5008-31 or -63. The information is given in accordance with our present-day knowledge and is meant to provide technical background. 1.5. 22
1.5. 23 iA Heißkanaldüsen Typ SLT/-DLT Customer information Vliesolen – Bamboo Fibre Reinforced Plastics Another advantage is that all the wear parts can be easily exchanged. This can avoid problems such as clogging of the nozzles, poor part filling, stringing and poor gate quality, and achieve shorter process times. By using a valve gate nozzle, the cycle time can be reduced by up to 20 %, depending on the application. Fig. Sample parts, produced with a 5SHT50 nozzle Thanks to the optimised temperature control in the hot runner nozzles the material could be processed at the temperatures recommended by the manufacturer. Depending on the base polymer and type of nozzle, the injection pressure fluctuated between 700 bar and 1100 bar. On the whole, the parts make a convincing impression. The sample parts produced with the nozzle with tip showed a good gate quality. It was possible to realise a maximum tear-off height of approx. 0.15 mm. As expected, valve gate nozzles can achieve optimum gate qualities with these types of materials too. Fig. mop holder made of vliesolen The thermal resistance of the bamboo fibre reinforced polymers is relatively high; after a simulated machine idle time of 10 minutes there is no problem in starting the aforesaid materials with the two hot runner nozzles in the test again. It is not necessary to have any higher nozzle temperatures. The parts do not show any thermal degradation. To summarise, it can be said that we did not experience any problem when processing the three tested plastics with bamboo fibre reinforcement in the hot runner system from GÜNTHER Heisskanaltechnik GmbH. This makes it possible to manufacture a product economically with a good price-performance ratio. Dipl. Ing. Jörg Essinger Applications Engineering Manager For any questions, please contact our Application Engineering department at + 49 (0) 6451 5008-31 or -63. The information is given in accordance with our present-day knowledge and is meant to provide technical background. www.guenther-hotrunner.com Subject to technical changes 7/12
Page 1 and 2: Heißkanaldüsen Customer informati
Page 11 and 12: Customer information Preventing flo
Page 17 and 18: Heißkanaldüsen Typ SLT/-DLT Custo
Page 21: Heißkanaldüsen Customer informati
Page 25 and 26: 1.5. 25 iA Heißkanaldüsen Typ SLT
Page 27: 1.5. 27 iA Heißkanaldüsen Typ SLT

Heißkanaldüsen Typ SLT/-DLT Customer information

Create successful ePaper yourself

Delete template?

Save as template?