Advantages of Injection Molding

Injection molding is the most commonly used manufacturing process for plastic parts. The use of injection molding varies greatly in size, complexity, and application. It requires the use of injection molding machines, plastic materials and molds. The plastic is melted in an injection molding machine and then injected into the mold cavity, where it cools and solidifies into the final part.

Injection molding is used to produce thin-walled plastic parts for various applications, the most common of which is a plastic housing. The plastic shell is a thin-walled shell, usually requiring many rib-shaped frames and protrusions inside. These housings are used in a variety of products, including household appliances, consumer electronics, power tools, and car dashboards, etc. Other common thin-walled products include different types of open containers, such as boxes and containers. Injection molding is also used to produce several everyday items, such as toothbrushes or small plastic toys. Many medical devices like valves and syringes, are also manufactured using injection molding.

6 major advantages of injection molding:

1. Ability to form complex shapes and details

Basically, customers can achieve whatever custom shapes/ forms they like. Other types of manufacturing may have difficulties, if possible, in doing so. Take cardboard boxes for example, make shaped cardboard boxes requires handwork, at rather dear cost. Even so, no all shapes can be realized in cardboard boxes.

2. Excellent surface finish

First, plastic material has greater plasticity in property compared to most other materials. Secondly, the surface finish is determined by the molds. So once the mold is set up as required, the desired surface finish is acquired upon injected. And absolutely all the same, as they are out of one mold.

3. Good dimensional accuracy

If you need absolutely accurate dimensions, then injection molding is no doubt the number one choice. The trick is with the mold design and construction. So strong molding capability is required. Good dimensional accuracy is guaranteed by precision molds.

4. High productivity

Once the molds are ready, all the work becomes repetitive injection process of machines. High efficiency, no break (except for necessary mold maintenance regularly).

5. Low labor cost

Labor is almost the biggest cost of all projects. Plastic injection molding involves little labor, especially for manufacturers with robotic manipulators in place. Once the initial fixed investment is made, the more you produce, the less breakdown cost will be.

6. Waste materials can be recycled

No waste! As waste materials will be easily recycled for future injection. 

Of course, everything has two sides. It's not all advantages only. The manufacture process of injection molding has its disadvantages as follows. What suits you is the best.

Disadvantages of injection molding:

1. Limited to thin-walled parts

2. High tool and equipment cost

3. Very long delivery time possible

Types of Packaging

Packaging is important and common either in the work or our daily lives. It’s so common that, to some degree, we are even not aware of its existence. It just seems to be an inherent part of everything.

Packaging involves a very wide range. There are many types of packaging in terms of material, packaging method, and purpose.

1. To categorize by material

Nowadays, so many materials have been used in packaging, such as paper, plastic, metal, glass, wood, linen, cloth, bamboo, rattan and grass, among others.

(1) Paper materials.

Common paper materials for packaging include honeycomb paper, kraft paper, coated paper, corrugated cardboard, chipboard, paper core, paper tubes, etc. 

(2) Plastic materials.

PP/PET strapping band, PP split film rope, wrapping Film, sealing tape, heat shrinkable film, plastic film, hollow board, etc.

(3) Composite flexible materials.

Flexible packaging, aluminized film, iron core wire, aluminum foil composite film, vacuum aluminized paper, composite film, composite paper, BOPP, and so on. 

(4) Metal materials:

tinplate, aluminum foil, barrel hoop, steel belt, packing buckle, aluminum blister, PTP aluminum foil, aluminum plate, steel buckle;

(5) Ceramic materials.

Ceramic bottles, ceramic cylinders, ceramic jars, ceramic pots

(6) Glass materials.

Glass packaging includes glass bottles, glass jars, glass boxes, etc.

(7) Wood materials.

Wooden packaging is made of wood products and artificial wood plates (like plywood, fiberboard), such as wooden boxes, wooden barrels, wooden cases, fiberboard boxes, plywood pallets, and wooden trays, etc.

2. By purpose of packaging

Packaging is not created equal. Broadly speaking, there are two types in terms of purpose: industrial packaging and commercial packaging.

(1) Industrial packaging

It function as a protection means in transportation, storage, and circulation, etc. It’s to business. Terms include shipping boxes, moving boxes, crates, pallets, etc.

(2) Commercial packaging

It plays a promotional or advertising function. It’s to consumers. Such packaging is basically the retail or gift boxes, those are parts of daily lives. 

3. By packaging form

It is divided into individual packaging, inner packaging and outer packaging;

4. By packaging method

It is categorized into waterproof / moisture-proof packaging, high barrier packaging, anti-rust packaging, anti-static packaging, water-soluble packaging, anti-ultraviolet packaging, vacuum packaging, anti-insect packaging, cushion packaging, EPS, anti-bacterial packaging, anti-counterfeiting packaging, tamper-proof packaging, nitrogen gas filled packaging, deaeration packaging, etc.

5. By packaging contents

This maybe is the most familiar categorization to common citizens. And such categorization involves the least jargon. There are food packaging, machine packaging, pharmaceutical packaging, cosmetics packaging, clothes packaging, chemical packaging, electronics packaging, military supplies packaging, etc., like watch holders.

Food packaging can be further categorized as beverage, fruit, cake, tea, meat, snacks and so on, such as candy boxes.

6. By degree of rigidness

Packaging includes rigid, flexible and semi-rigid packaging according to the degree of rigidness.

(1) Rigid packaging.

A rigid box is shipped as it is, and not easy to deform(also called setup box).

(2) Flexible or soft packaging

It refers to those containers whose shapes can be changed after filling or taking out the contents. An easy example of this is the stand-up pouch.

(3) Semi-rigid packaging

It falls between rigid and flexible. Corrugated cardboard boxes, folding boxes, lightweight plastic containers and plastic hoses, etc. are all semi-rigid packaging.

What Plastics Can Be Injection Molded?

What plastics can be injection molded? That's a long list! Simply put, almost all thermoplastics can be injection molded. To consumers, the most common plastics that can be injection molded may be PP, PS, and ABS, etc. Below is a sum-up:

1. PC/ABS blends

That is, the blends of the two types of plastic: polycarbonate and acrylonitrile-butadiene-styrene copolymer. The typical applications of such plastic include, but not limited to: computer housings, electrical appliances, garden machines, automotive parts /dashboards, vehicle tire fenders, etc. 

2. PC/PBT Mixture

Mixture of polycarbonate and polybutylene terephthalate. Mainly used for injection of products that require chemical and corrosion resistance, thermal stability, impact resistance and geometrical stability, such as car bumpers, gear boxes, etc. 

3. HDPE (high-density polyethylene)

Typical applications: refrigerator/freezer bins, storage containers, household kitchenware, sealing lids, etc. 

4. LDPE (low-density polyethylene)

Typical applications: bowls, cabinets, pipe couplings, etc. 

5. PEI (polyetherimide)

It’s an amorphous, amber-to-transparent thermoplastic. Applications: automotive industry (engine parts such as temperature sensors, fuel and air processors, etc.), electrical appliances and electronic equipment (electrical couplings, printed circuit boards, chip housings, explosion-proof boxes, etc.), product packaging, Aircraft internal equipment, medical industry (surgical instruments, tool housings, non-implantable instruments). 

6. ABS plastic 

It is synthesized from three chemical monomers of acrylonitrile, butadiene and styrene. It's also one of the most common engineering plastics. ABS has excellent chemical & electrical properties, it‘s resistant to heat, impact, low temperature and chemicals. It's suitable for making general mechanical parts, wear-reducing and -resistant components, transmission parts and outdoor waterproof watch boxes, etc. Besides, because of its good dimension stability, ABS plastic is often used for 3D printing.

7. PA6 (Polyamide 6 or Nylon 6)

With good mechanical strength and rigidity, it is widely used in structural components. It’s also used to make bearings thanks to its good wear resistance. 

8. PA66 (Polyamide 66 or Nylon 66)

Compared with PA6, PA66 is more widely used in the automotive industry, instrument housings and other products that require impact resistance and high strength. 

9. PBT (polybutylene terephthalate)

PBT is one of the toughest engineering thermoplastic materials. It is a semi-crystalline material with very good chemical stability, mechanical strength, electrical insulation properties and thermal stability. Applications include: household appliances (food processing blades, vacuum cleaner components, electric fans, hair dryer housings, coffee utensils, etc.), electrical components (switches, motor housings, fuse boxes , computer keyboard keys, etc.), automotive industry (radiator grille, body panel, wheel cover, door and window components, etc.). 

10. PC (polycarbonate)

Typical applications: electrical and commercial equipment (computer components, connectors, etc.), appliances (food processors, refrigerator drawers, etc.), transportation industry (vehicle front and rear lights, dashboard, etc.). 

11. PET or PETE (polyethylene terephthalate)

PET is the most common thermoplastic polymer in the polyester family. Typical applications include: automotive industry (structural devices such as mirror boxes, electrical components such as headlight reflectors, etc.), electrical components (motor housings, electrical couplings, relays, switches, microwave ovens Internal device). Industrial applications (pump housings, manual instruments, etc.). Due to its property of high tenacity, it's also widely used for synthetic fabrics.

12. PMMA (Polymethyl methacrylate)

Typical applications: Automotive industry (signal lights, instrument panels and other temperatures, then transparent products can also be obtained using non-filled PET materials.

 

13. POM (polyoxymethylene)

Also known as acetal, polyacetal, and polyformaldehyde. POM has a very low friction coefficient and good geometric stability, especially suitable for the production of gears and bearings. Because it has high temperature resistance, it is also used in piping devices (valves, pump housings), lawn equipment, etc. 

14. PP (polypropylene)

PP is one of the plastic that relates most closely with our life. It's widely used in many industries: automotive industry (mainly using PP with metal additives: fenders, ventilation pipes, fans, etc.), appliances (dishwasher door liners, dryer ventilation pipes, washing machine frames and covers, refrigerators Door pads, etc.), daily consumer goods (lawn and garden equipment such as lawnmowers and sprinklers, water bottles, jewelry cases, etc.). PP material can work with hot runner system. 

15. PPE(polyphenylene ether)

Also known as PPO (polyphenylene oxide). Typical applications: household appliances such as dishwashers, washing machines and other electrical equipment like controller housings and fiber optic connectors. 

16. PS (Polystyrene)

It has high transparency. Typical applications: product packaging, household items, tableware, trays, etc., electrical (transparent containers, light source diffusers, insulating films, etc.). 

17. PA12 (polyamide 12 or nylon 12)

Typical applications: water meters and other commercial equipment, cable sleeves, mechanical cams, sliding mechanisms and bearings. 

18. PVC (polyvinyl chloride)

Water supply pipes, domestic pipes, house wall panels, commercial machine housings, electronic product packaging, medical equipment, food packaging, etc. 

19. SA (styrene-acrylonitrile copolymers)

Mostly common articles out of plastic injection molding from SA include electrical sockets, housings, household commodities, kitchen appliances, refrigerator devices, TV bases, cassette boxes, etc., automotive industry (headlight box, reflective environment, instrument panel, etc.), household items (tableware, food knives, etc.), and cosmetics packaging, etc.