PLA Injection Molding

Inox PLA Injection Molding

Are you looking for a perfect custom supplier for your business? Inox Cast can provide perfect customizations of PLA injection molding at great prices.

Inox Cast PLA injection molding has a lot of applications and purposes that able to produce salable disposable products at perfect durability.

Inox Cast PLA injection molding is able to produce a lot of biodegradable and bio-based products like disposable cups, bottles, Tupperware, meal trays, plates, spoons, and fork, drinkware, and more types of products.

We can custom your ideal sizes and designs according to your handled products. We ensure your ideal sizes, designs, colors, types of products, and more. PLA or polylactic acid is an injection molding grade that widely applicable for making biodegradable products like kitchenware, grocery bags, and more.

Inox Cast PLA injection molding is a low heat resistant product with 210C of melting point. We design PLA injection molding for this type of fabrication and support to produce this type of product supplies. We ensure the features of our PLA injection molding, specifications, the design of your deal products, size, and ensure your desired texture, surface, and more.

Our PLA injection molding has different processes to make different types of biodegradable products with different numbers of cavities. Inox Cast PLA injection molding has perfect injection pressure base on your product thickness and types.

Our PLA injection molding has melt temperature has suitable control from 170 up to 90 melt temperature and the mold temperature is about 10 to 25C. It has a drying process that performs from 2 to 6 hours base on your product.

We can custom all your desired products and supply them according to your request. Send your details and drawings so we can satisfy your PLA injection molding orders.

You can trust our 20 years of service since we are trusted in customizing and producing the best PLA injection molding and other related products.

Send your inquiries so we can satisfy you more!

PLA Injection Molding: The Ultimate FAQ Guide

This guide covers all information you are looking for about PLA injection molding.

Whether, you want to learn about features, specifications, or the actual process – you will find all information right here.

Let’s dive right in.

1.  What Is PLA Injection Molding?

This is the process of producing parts or molds from PLA (Polylactic Acid) material which is a natural polymer that can biodegraded easily.

PLA injection molding

PLA can be used to produce different parts for a wide range of applications.

2.  What Are The Benefits Of PLA Injection Molding?

-Very efficient and fast production: When compared to other methods, PLA Injection Molding is very fast and cost effective.

The short period between cycles enables production of volumes of parts within a short period of time.

-Complex part design: This process can make highly complex designs especially if the designs are properly put into place to avoid processing mistakes.

-Enhanced strength: the designer of parts should be able to know whether the part has to be rigid.

Or flexible and he also needs to know what the part will be used for and the environment it will be used in.

-Flexibility: There is a wide variety of material and color to choose from when making a design for parts.

-Reduced waste: this process involves the regeneration of excess plastic, it is recycled and used to produce more parts.

-Low labor costs: This process uses an automated tools and machines hence less labor needed.

3.  Which Features Make PLA Perfect For Injection Molding Process?

It is classified under thermoplastic which means it changes to liquid when it reaches the melting point.

This feature allows the PLA material to be heated and cooled and heated again without degrading it.

That is why it can be injection molded into useful parts.

The residue can still be recycled and produces parts with the same quality as the original material.

4.  How Do You Choose Mold For PLA Injection Molding?

When choosing a mold for the PLA injection molding, consider the factors listed below;

–Specifications and model: It is important to go for the right model of the molding machine.

The specifications are included in the product instructions by the manufacturers.

The instructions given will also include the parameter values of the machine.

-Dimensions of mold: This should be checked at all times since it what is needed to produce the right product.

The height, the length the width are of more importance.

The molding machine should also be able to eject the molded product.

–Injection speed: The injection pressure, injection rate and injection pressure should be put into consideration when choosing screw diameter.

-Available capacity: the capacity requirements of a product should be considered when choosing a mold for its production.

– Cycle time: products that require short cycle period, need fast injection molding machines which are also a bit expensive.

-Core pullers: The machine of choice should contain enough core pullers.

5.  What Is The Process Of PLA Injection Molding Process?

-Cleaning – Before introducing the PLA material, the injection molding machine must be properly cleaned as well as the blending and feeding material.

-Injection molding machine settings – conventional injection molding equipment can be used to process PLA.

The temperature for the mold should at 90-100 degree Celsius to produce a product with higher heat resistance.

The duration needed to obtain the highest crystallinity in the molding machine depends on the formulation of the PLA, part design and mold temperature.

The part is still flexible until it is cooled down to the temperature of about 55°C.

-Optimizing cycle – it is important to inject mold of the right temperature, this will ensure the shortest cycle time.

After the production of the amorphous product and ejection from the mold, apply suitable conveyer belts and collection equipment to prevent deformation.

6.  What Are The Main PLA Injection Molding Technique?

Hot runner molds: made up of two plates heated with a multiple system.

Which maintains an unchanging temperature keeping the liquid thermoplastic within the runners at the same temperature level as the cylinder.

hot runner mold

The hot runners deliver the liquid plastic to nozzles that fill the core mold to make the final product.

Cold runner molds: have two or three plates held in the mold base.

The thermoplastic is injected into the molding machine through the sprue filling the runners then into the cavities.

cold runner mold

The runners are not heated and they deliver the molten plastic into cavities.

Blow molding: plastic forming process that creates hollow plastic products out of thermoplastic materials.

A plastic tube (preform) is heated and inflated. The preform is shaped by placing it between two dies.

blow molding

 The supply of air will expand the tube and form shape of part.

Insert injection molding: the process of making molds around inserts or other non-plastic parts to form plastic parts.

insert injection molding

7.  Which Surface Finishes Can You Apply On PLA Plastic Injection Molded Parts?

Surface finishing for injection molding is meant to decrease or increase the roughness of a mold.

–Glossy Injection Molding Surface Finish: very shiny and very smooth surface which is mirror like and is made with diamond powder in oil.

–Semi-Glossy Injection Molding Surface Finish: smooth but not as glossy and made by use of sand paper and are mostly used for external parts

-Matte plastic Injection Molding Surface Finish: the surface has a rougher texture and less shine made by use of stone powder polish.

–Textured plastic Injection Molding Surface Finish: produces a rough and less shiny  surface which is achieved by use of sandblast.

8.  Which Parts Can You Make Using PLA Injection Molding Process?

PLA injection molded parts may include;

Detachable surgical suture, disposable infusion equipment, fast food lunch boxes, health care fabric, non-woven fabrics, agricultural fabric, sanitary products, dishcloth, sanitary products,  tent cloth, outdoor UV resistant fabric and floor mat.

9.  What Are The Common PLA Injection Molding Defects?

Weld Lines on an injection molded part: a linear mark on the surface of the part, it can weaken the mold.

It happens if a stream of molten plastic resin within the mold cavity has to go round an internal barrier and combines with other resin on the opposite side of the barrier.

Possible solutions are as below;

-Change the position of runners and gates so that resin can flow round the barrier via another direction

– Modify cooling temperatures and resin

-Adjust cooling circuits

-Apply dark colors, use matte surface finish.

Gate witness marks: may be burrs, dimples or raised ridges found on the produced part.

This is caused by the waste sprue and cannot be totally eliminated since it forms part of the product.

However, it can be controlled by disguising the witness at some other feature within the part.

Or by using a fan gate and distributing the resin around a wider area with low pressure.

Parting lines: a thin joint which is raised caused by joining the two mold parts together leaving that joint line.

It cannot be eliminated but can be mitigated through; smooth sanding and repainting.

Or disguising with rough surface finishes or camouflaging the line by integrating it with other linear features.

Sink Marks on Molded Parts: an unwanted depression in the surface of the produced part which happens when the molten resin gets into contact with the tool wall .

Hence cooling down and forming a shrink before the surrounding area does.

It can be minimized by:

• Maintaining consistent wall thickness
• Building more cooling channels in the appropriate areas
• Balancing injection temperature
• Pressure and cooling times
• Disguising with darker colors and matte finishes.

Short shorts: this is a part which is not completely formed because the gate shut off before the injection mold was filled maybe due to low pressure or poor part desisn.

These are best prevented during the designing stage as below;

Make the gate near the thin areas for a first fill.

Let gas escape by adding vents

Adjust wall thickness where possible

Do another design for the runner systems.

10.  What Should You Consider When Choosing PLA Injection Molding Machine?

There are many things to consider when choosing a molding machine for the parts. Some are discussed below;

Short size: The maximum amount of molten plastic that can be injected into the molding cavity by an injection molding machinery.

Look for machinery that can produce 30-40% greater short amount than what the product need.

Tonnage: is measured by the number of tons the machine is able to press together the platens.

That hold the mold cavity to form the plastic which is injected into the cavity to make the desired part.

Platen size: tool meant to hold the mold cavity should be of the size suitable for the part design and quantity.

Tie bar spacing: the amount of space between the horizontal tie-bars of the injection molding machine.

It determines the amount of molten plastic that can be injected into the cavity.

Ejector stroke: the process of pushing out the final product. This should be designed in a way to protect the final product from getting damaged.

11.  What Is the Recommended PLA Injection Molding Temperature?

Melt Temperature      340-370˚F 170-190˚C

Mold Temperature     50-75˚F 10-25˚C

12.  Is PLA Injection Molding Recommended At Amorphous Or Crystalline Morphology State?

It can be in either of the two states, however, the application temperature and presence.

Or absence of a nucleating agent will determine whether the part will be in amorphous or crystalline morphology state.

Applications of temperatures below 50^oC allows the mold in amorphous morphology.

This does not need nucleating agents and it means maintaining the mold temperature below 24^oC to avoid the parts sticking together.

Applications that are exposed to temperatures above 55^oC, will need the mold in crystalline state. This involves a nucleating agent and the mold temperature should be above 82^oC.

13.  Which Factors Should You Consider During PLA Injection Molding Process?

Barrel Temperatures: the barrel temperatures affect the flow and the cooling of the mold within the molding cavity hence should be considered carefully.

Plastic Flow Rates: this should enable the molten plastic to be injected at a high pressure and as fast as possible and it should be 99% full.

The flow rate also determines the viscosity of the mold as it moves in the mold cavity.

Plastic Pressure or “Screw Back” Pressure: If injection pressure is very high, the flow-ability of the plastic is also high and this can cause issues like flash or overflowing.

PLA injection molding process

If pressure is very low, the flow of the plastic is reduced and can cause issues like void or bubbles.

Nozzle Temperatures: must be lower than that of the barrel to avoid the decomposing of the plastic.

Plastic Cooling Rates and Times: cooling rate should rely on the manufacturers recommendation and also the client’s requirement.

Cooling time is determined by the design of the part to be produced.

Plastic Melt Temperatures: all the three factors shold be put to consideration; the barrel, the nozzle and the mold.

14.  How Does Injection Molding  Standard PLA Compounds Compare To High Heat PLA Compounds?

Standard PLA compounds will make an amorphous structure while high heat PLA compounds will make a semi-crystalline structure.

High heat PLA are obtained through combining PDLA and PLA homopolymers while standard PLA are homopolymers and have high melting points and a higher crystallization rate.

standard PLA injection mold

Different molding temperatures are recommended to both standard PLA and high

heat PLA compounds.

15.  Why Should You Dry PLA For Injection Molding?

PLA being a hygroscopic thermoplastic, can easily absorb water from the surrounding.

The presence of moisture can decompose PLA at the melt phase, resulting into a reduced molecular weight and properties lost.

It is important to dry up all compounds with PLA in them to 0.002% moisture content through a desiccant dryer which has the capability to deliver air at -40^oC dew point.

16.  What Is The Recommended Mold Design For PLA Injection Molding?

The mold used for PLA parts should have a hotrunner system with low shear with no dead spots in the complex to avoid degrading the material.

The nozzle with an open channel should be heated to enable a perfect flow of the molten material in the cavity.

A sprue can be used in place of a hotrunner, the total draft angle of sprue should be above 6^o .

17.  How Can You Optimize Cycle Times During PLA Injection Molding Process?

In order to have a shorter cycle time, use the appropriate mold temperature.

Use internal and external thermo couple to measure temperatures for different parts.

Heat losses can lead to low temperatures hence affecting the production process.

Use special collection boxes for the finished for product to avoid deformation.

Crystallization process takes much longer hence forming crystalline product might need a longer cycle time than when producing an amorphous product.

18.  What Are The Applications Of PLA Injection Molded Parts?

-Used for medical and food purposes and also used for 3D printing feedstock in desktop fused filament fabrication 3D printers.

-PLA degrades into lactic acid hence can be used for medical implants like screws or plates.

-PLA is used as a decomposable packaging container, film or for cups and bags.

-It is used with disposable tableware, compost bags, loose fill packaging and food packaging.

-PLA is used for disposable clothing, upholstery, feminine sanitary products and nappies.

More Resources:

Die Casting

Surface Treatments

Injection Molding

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