Composite Technologies

Composite technologies highlighted below feature abbreviation and full-form technologies. Since technologies are mostly referred to by their English abbreviations, their full forms and Turkish equivalents are used less frequently. HP-RTM can be used as "high-pressure resin transfer molding." SRIM can be used as "structural reaction injection molding." Since these types of technologies generally originate from abroad, they continue to be used as they were first named. However, the correct approach is to use properly Turkish-localized terminology. I addressed this topic in my congress presentation titled "Using Terms Correctly, Using the Correct Terms." Particularly when defining raw materials, our sector uses trade names assigned by manufacturing companies instead of chemical definitions, and since these names are generalized without detailing specifications such as MFI and impact resistance, we cannot understand each other sufficiently. Composites are divided into two categories: thermoplastic and thermoset. Thermoset Composites: Can be examined in two sections as short continuous fiber composites. Short Fiber Composites: Parts can be produced using SMC (sheet), BMC (compression molding), SCRIMP (resin transfer molding), spray and injection methods. Long Fiber Composites: Parts can be produced using hand lay-up, filament winding, spray, RTM, autoclave, SCRIMP, RIFT, VARTM methods. I recall that during my education in the 1980s, using the hand lay-up method, I produced car front hood and trunk lid parts by creating a wooden mold and painting them red, producing Ferrari-like car exterior parts. It was quite an enjoyable work. However, this method is slower compared to other methods. Thermoplastic Composites: Again divided into two sections as short and continuous composites. Short Fiber Composites: Can be processed using injection and blow molding methods. Continuous Fiber Composites: Processed using tape winding, compression molding, and autoclave methods. Successful applications in aerospace and wind energy have created opportunities for the transition of composite materials in the automotive industry. Currently, in terms of cycle time, work must continue with relatively long cycle times. Tailor-made production work in sports cars finds considerable space for itself. HP-RTM has established a very good position in the automotive industry both in terms of cycle time and technology, in both cycle time and production ease. Brake pedals, many exterior parts and even multiple chassis components have been produced and then successfully assembled using HP-RTM. Work is being conducted for engine blocks. Combustion chamber cylinder liners fitted as sleeves will achieve good progress in vehicle weight reduction.

Advantages of Composite Material Use

Design constraints found in metal parts do not exist in composite design, creating a broad design perspective. • Part count reduction can be easily achieved in design. • Component life increases due to absence of corrosion risk. • Fatigue is lower. • Safety increases due to impact damping properties. • Noise levels decrease. • Electrical properties are good. • Manufacturing ease. Applications such as welding or riveting multiple parts in metal components are eliminated with composite material use. • Most importantly, weight reduction emerges. • The benefit of weight reduction is lower fuel consumption. • Weight reduction also means low emissions with an environmentally conscious approach.

Disadvantages of Composite Materials

• Material costs remain high today. • Qualified personnel are required in production. • Improvement work must be done on cycle times. • Let us examine one simple method and one high-engineering method, HP-RTM, from production methods.

Hand Lay-Up

Applications include wind turbine blades, boats, plates.

Advantages

• Easy to apply, so it can be learned quickly. • Low-cost resins can be used since it can be used at ambient temperature. • Long fibers can be used.

Disadvantages

• Air voids can form. • Production environment must be ventilated. • Requires hand skill.

High-Pressure Resin Transfer Molding

Use in car parts is quite widespread.

Application

Felt or fabric is pre-shaped and placed into a heated mold with robot assistance, resin is injected at high pressure. After cure time, the part is removed from the mold again with robot assistance. Remaining resin in the mold is cleaned with robot assistance and prepared for the next cycle.

Advantages

• Fast pre-shaping time. • Fast injection. • Fast cycle with fast reactive resin system. • Void reduction. • Good surface quality. • Repeatability. • Better tolerances in thin walls

Use of Plastic Instead of Metal

The use of plastic composite materials instead of metal is expanding from fields such as aerospace, aircraft industry and wind energy to the automotive sector and then to the white goods manufacturing sector. Particularly the production of parts manufactured by aluminum casting with composite materials can be preferred both because production conditions are healthier and because of good repeatability. European countries have acted faster in this regard. In our country, since aluminum casting labor is cheaper compared to Europe, feasibility analyses come out even or remain one level ahead for today. Feasibility is more suitable for metal-produced parts. The use of composite materials instead of metal should be examined by R&D and production engineering units for every part produced with metal and transition work should be carried out, which will provide benefits for both weight reduction and process shortening. In sheet metal part production, using methods such as cutting, bending, deep drawing, riveting and welding to obtain a part, we can obtain the same part using composite production methods with a single process method. Metin Bilgili - Founder / MB Plastic Training Consulting