Spray Urethane skins Aliphatic vs Aromatic Spray Urethane Vacuum Formed skins Male vacuum forming Female vacuum forming Slush & Rotocast skins Slush molding Rotocast molding Foam In Place for Soft IPsSOFT SKIN TECHNIQUES

Spray Urethane Description Spray Process Flow Spray PU Benefits Spray PU vs Alternative Skin Technologies Spray PU Validation Test Results SPRAY URETHANE PROCESS

Spray PU is the process of spraying polyurethane onto a tool to form a soft skin for an automotive part.

The urethane is typically two components: isocyanate + polyol which react in the tool or mixing head to form one polyurethane skin.

Typical Automotive products include: Instrument Panels Door Panels Floor Consoles Seats, Seat Backs, and Headrests Headliner & Packaging Trays Carpetless FlooringSPRAY URETHANE PROCESS

Vacuum Forming Process Flow Male vs Female Vacuum Forming Description Vacuum Forming Tooling & Equipment Requirements Material Options Design & Tooling Guidelines VACUUM FOAMED SKIN

A heated tool, usually of electroformed nickel construction is coated on the interior cavity with a thermoplastic material which is subsequently cooled and peeled from the tool. The resulting skin is molded in a separate tool using the conventional F.I.P. process.

2004 Cadillac XLR Instrument Panel Process: Slush Molded Skin, Foam In Place Material: Thermoplastic UrethaneSLUSH MOLDING PROCESS DESCRIPTIONS

ProUse less material per part than Rotocasting (more uniform skins, thinner skins)Process accommodates undercuts in part design better than spray urethane. (Does not require line of sight)Can be molded to color (no paint)

Con:Tool life can be shorted due to thermal shock (depend on product design)Texture definition inferior to spray urethane (PVC)Environmental performance of PVC less than spray urethaneSLUSH MOLDING PROS AND CONS

SLUSH MOLDING W/HOT AIR PROCESS

Nickel Tool is heated to 400 500oF depending on material. (Tool can be heated by Forced Air, Hot oil or Hot (Fluidized Bed) Sand.

Heated Nickel Tool is attach to the Powder Box.

Rotating Tool Box as needed, then return to Original Position.

Separate Nickel Tool Box and Powder Box.

Reheat to cure skin.

Cool Tool to 120o10oF.

De-mold Skin and Clean the tool.

SLUSH MOLDING PROCESS STEPS

Nickel Tooling is used in Production Application Almost Exclusively. This tooling is made by electroforming or nickel vapor deposition. Both processes will be described in a separate documents. Lear has electroforming capability in house. 2004 Subaru Legacy/Outback TPU Skin with Nickel Tool 2004 Subaru Baja PVC Skin with Nickel ToolSLUSH MOLDING TOOL

Forced Air Tools mounted on carts are moved through an oven built of several zones, each one at a controlled temperature, the last zone to fine-tune the exact temperature for slush powder contact.

Hot Oil Self Contained Modules are built that provide the heating and cooling oil to tubing circuits soldered to the backside of the tool. The typical cycle takes 4-5 minutes, button to button.

Hot Sand (Fluidized Bed) By heating with sand the heating time is the shortest and it provides even heat. But mold life expectancy is can be less than other methods.Heat as fast and consistent as PossibleSLUSH MOLDING HEATING METHODS

SLUSH MOLDING HEATING OWEN

SLUSH MOLDING POWDER BOX

Low Temp at Powder Contact with Tool Results in Pin Holes on skin surface Non-uniform temperature across tool surface Pinholes, thick-thin areas, torn skins. Tool Cracks caused by stress in tool aggravated by rapid cooling. Glossy Skins usually result from build-up of plasticizer on tool surfaces and excessive release agent. Tool must be cleaned to reduce gloss. Torn Skins Skins that are too thin or under cured are too weak to withstand de-molding stress. Contaminated Powder in Powder box Foreign material, typically lumps of partially-cured powder that fall back into the powder box and reappear on the surface of subsequent skins. Sieving the powder in the box minimizes this problem.

ISSUES IN SLUSH MOLDING

Rotational Molding

Rotational Molding, Rotocasting, is a process that is used to make seamless products from a variety of plastics by the controlled application of heating, rotation and cooling of steel, nickel, or aluminum tooling.

ROTATION MOLDING PROCESS DISCRIPTIONS

ProTooling cost per tool significantly less than injection molding.Compared to injection and blow molding, the capital investment is less.Hollow parts can be formed (difficult with injection molding)The plastic is lower stress than injection molding because the plastic shape is not formed under pressure.

Con:Molding cycles are very long compared to other processThe mold is usually assembled/disassembled manually, so it is a labor intensive processThe process is not very energy efficient

ROTATIONAL MOLDING PROS AND CONS

Cycle TimeROTATION MOLDING PROCESS FLOW

Tool cavities mounted in frames supported by a rigid arm are charged with plastisol (Liquid) or drysol (Powder) and the charging opening (Lid) or dual cavities are sealed. This set of tools is indexed into a forced air oven.

The arm is equipped with gears that allow independent rotation of the tool frames on both axes. Rotation ratio is a term describing the quotient of the revolutions per minutes on each axis.

Rotating the tools in the manner allows the plastic to flow evenly against the side walls of the tools. rotation ratio is adjusted until no centrifugal force is applied to the material (which adversely affects even distribution).

ROTATIONAL MOLDING PROCESS STEP 1

After a few minutes (typically 5-8), the plastic has been distributed onto the side walls and the arm is indexed into the cooling zone.

Forced air and spray mist of water is typically applied to cool the tools and frame for safe de-molding. After (5-8) minutes, this arm is indexed into the de-mold station.

The lids (or tool cavities) are separated and the product is de-molded by peeling.

ROTATIONAL MOLDING PROCESS STEP 2

There are many factors that affect the feasibility of the using a resin in rotomolding. Polyethylene is by far the most common used in 90% of applications. Other materials are PVC, ABS, Nylon, PC, high impact polystyrene, acetal, and crosslinked polyethylene. ROTATIONAL MOLDING MATERIAL OPTION

Foam In Place

Tooling: Cast Aluminum Tool base CNC Cut Part Model from RenWood or other prototype material use Model + Cast Aluminum base to epoxy cast final Aluminum Foam Tool Repeat for other of final foam tool. CNC cut auxiliary Aluminum tooling inserts. Capital Equipment: Carousel style line: operators are stationary, line moves. stand alone Foam machines: one operator typically walks back & forth between 2 machines.FOAM IN PLACE TOOLING AND CAPITAL EQUIPMENT

Foam in place edge seal off options Typical sections of edge sealing off with beads water jet cuttingFoam flow is sealed off with beads on the edges and run off will be trimmed later by water jet cutting

Foam flow sealed off with inflatable sealInflatable sealFoam in place edge seal off optionsedge sealing off with inflatable sealTypical construction

Various foam pouring alternatives 7 hole pattern6.35mm holes in a 25mm diameter25 cross GateCylinder with inner dia 25 , with cross ribs the hight is 3.5mm

Foam in place edge seal off optionsTypical sections for Foam and skin section with tighter radii condition and seal of with the tooling.

Executions for foam and skin undercut in the foam tool.

**************************