Thin wall injection molding

NAIK DEVANG

Why Design With Plastic ?

• Excellent Barrier resistance• Non Toxic Properties• Odorless• Easily formed into complex

shapes

• Wide choice of appearance, colors and transparencies

Material property for Thin Wall Molding

• Improved flow ability : permits luxury with odd geometry in shapes

• •Low density & packing weight permits affordable cost to performance

• •Excellent toughness to withstand against content• •Optimal combination of flow, impact resistance &

stiffness

• •Stack ability for ease of bulk transport.• •Excellent stiffness for the freedom of attractive shape

& size• •Superior clarity & crystalline for the product

visibility.

Thin-Wall Injection Molding

• What is “ Thin Wall Injection Molding’’ ?– • Wall thickness often <0.6 mm– • Parts with flow ratio >150– • High Injection pressure– • High Injection speed– • Applications for containers in

packaging and storage as well as disposable use.

Fast Cycling molding – Key Requirements

• A mold which is capable to run fast cycles for a long period

• A capable injection molding machine• Consistency in Raw Material• Production environment with

essential well define Auxiliaries • Cooling water for molding machine• Fast and precise machine

movements for prolonged period..• Chilled water for mold• Energy saving operation

Reasons for “Thin Wall Injection Molding”

• Less material per part means less material cost per part

• Thinner wall thickness means shorter cooling time and therefore shorter cycle time resulting towards,

•Higher Productivity–High Profitability

Machine Selection Criteria

• Higher cavity pressures result in higher necessary Clamp forces.

• High Injection Pressure with > 2200 bar.

• High acceleration with accumulator-power > 350 mm/s.

• Faster Response of controller within 2 mili seconds to be synchronized by Smart hydraulic for the shortest cycle time.

Machine Setting for “Thin Wall Injection

Molding”

• Nearly no holding or packing necessary• Often Injection against mechanical stop in

the injection unit with no cushion• Start injection before clamp force is fully

built for better venting• Short cooling time• Optimized machine movements for short

cycle time• Parallel machine movements

Selection of Injection Unit• Important factors:

–•Screw torque –•Melt temperature–•Injection rate and pressure–•Cycle time - cooling time –•Plasticizing rate –•Repeatability–•Screw Geometry

Mould Selection Criteria for “Thin Wall Injection Molding”

• Short runner channels to reduce flow length and pressure losses

• • Hot runner is preferred compared to cold runner systems

• • Gate bigger in size because of higher volume flow through cross section

• • Special arrangement for gating like cascade or sequential injection; per part multi-gating

Limitations of “Thin-Wall Injection Molding”

•To high material stress• • Flow properties of material• • Residence time for material

because of smaller shot weights• • Economical situation, related

to investment costs compared advantages

•Thank you

TWIM