plastic assembly by heat staking.ppt

CONFIDENTIALRohan Kumbhar (RKUMBHAR) ODEC PUNE : 20th July 2012

HEAT STAKING


HEAT STAKING :

Heat staking is a specific type of plastic assembly. Plastic welding is a process by which two or more plastic components are permanently joined. More accurately, it is any one of several plastic assembly processes. However, plastic welders can use also heat staking to join plastic components to dissimilar types of plastics – or even non-plastic components like wood or metal.

The heat staking process is a relatively quick and simple one. Quick in that it generally takes only one to five seconds. Simple in that the heat staking concept is a mechanical one – and fairly basic, at that.In heat staking, a plastic stud protruding from one component fits into a corresponding hole in the second component. The tip of the stud is heated to the point of softening, at which time, it gets flattened, forming a "head" that is larger than the opening in the other part. This keeps the two parts from separating.

PROCESS :

The hot bar, with a defined cavity, comes down on the stud. Force is applied on the stud and once the required force is achieved, the heating process starts. The force together with the pre-set heat will soften the stud and mould it into the required shape and at the same time fix the second part Cool down, still under force, to below the glass transition temperature and finally lift the hot bar.


ADVANTAGES OF HEAT STAKING :

1. Little stress on the stud because of heat.2. Heat staking process is a very clean form of thermal assembly.3. Glass filled plastic can be deformed without causing embrittlement .4. After the heats staking process is done, physically and visually the heat staked product appears to be an extension of the moulding process.5. The heat staking process usually takes only a few seconds6. Plastic parts may be joined to non-plastic (e.g., wooden or metal) pieces

MATERIALS SUITABLE FOR HEAT STAKING :

1. Lubricious materials such as PTFE2. (ABS), poly styrene (PS), polypropylene (PP), polycarbonate (PC) and glass-rein forced nylon (GFN).3. Brittle materials such as 50% glass-filled PPO


TYPES OF HEAT STAKES AND DESIGN RULES :

1. STANDARD FLARED STAKE :

2. SPHERICAL STAKE :


3. HOLLOW STAKE :

Staking a hollow boss produces a large, strong head without having to melt a large amount of material. Also, the hollow stake avoids sink mark on the opposite side of the component and enables the parts to be reassembled with self-tapping screws should repair and disassembly be necessary.

4. KNURLED STAKE :

The knurled stake is used in those staking applications where appearance is not critical. Since alignment is not an important consideration, the knurled stake is ideally suited for high volume production. Knurled tips are available in a variety of fine, medium and coarse configurations.


5. STANDARD FLARED STAKE :

The flush stake is used for applications requiring a flush surface. The flush stake requires that the retained piece has sufficient thickness for a chamfer or counter bore.


DESIGN RULE DESCRIPTION :

1. B-surface flatness adjacent to weld head - Welded surfaces to be parallel at weld

point .

Gap at lower edge - potential rattle.


2. Heat staking gun considerations :

25 mm

25 mm

45-60 mm

1. Clearance around the heat staking boss = 25 mm2. Distance between 2 heat staking bosses = 45 mm to 60 mm


APPLICATIONS :

1.Automotive industry for door panels, map pockets, light-pipe staking, consoles, arm rests and switch clusters. 2. Medical applications include blood-processing equipment, chemical pumps, fittings, flow meters, IV drug delivery and surgical instruments.

3. Consumer Product applications include personal computers, portable telephones, laser printers, copy machines, video games, speakers and appliance components.

4. Industrial applications include conveyor systems, gears, pulleys, couplings, and motor housings.

Heat Staking DisassemblyDisassembly for recycling or reworking of heat-staked assemblies also can be accomplished using precise heat and pressure. High-heat piercing with a 60° pointed probe will reflow the stud-head material, allowing a quick, clean removal of the stud head. Reassembly can be performed on reworked parts using alternate holes and self-tapping hardware, or a second set of posts for staking assembly can be performed on reworked parts using alternate holes and self-tapping hardware, or a second set of posts for staking.


1. X-152 COUPE TRUNK TRIM

APPLICATIONS IN ON-GOING PROJECTS :

Heat staking between side trim upper and lower (Both LH and RH side trims)


Heat staking between load floor substrate and EPP block. Also, plastic washers are provided to avoid any damage to the part while heat staking process.


Heat staking between bulkhead trim substrate and EPP block.

Also, plastic washers are provided to avoid any damage to the part while heat staking

process.


Heat staking between fixed shelf and slide bolt carrier.


Heat staking between scuff plate and neoprene rubber cover.


2. X-152 CONVERTIBLE TRUNK TRIM

Heat staking between air vent bracket and retaining ring (Both

LH and RH side trims)


Heat staking between air vent bracket and retaining ring (Front

end transverse trim)


Heat staking between scuff plate and neoprene rubber cover.


INDUSTRIAL APPLICATIONS :


Thank you

plastic assembly by heat staking.ppt

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