Plastic Injection Molding Guide: Top 10 Materials To Use

Hi! Let’s talk about plastics. Plastic is stuff we use to make things. Injection molding is a way to make plastic things. At Istar Machining, we know a lot about plastics!

What is Injection Molding?

Injection molding is when we heat up plastic until it gets soft. Then we push the soft plastic into a mold. The mold is like a shape. When the plastic cools, it stays in that shape!

Our team at Istar Machining can help make plastic parts for you. We use CNC machining service to make the molds too!

Top Plastic Materials We Use

Let’s look at the best plastics for making things:

1. Polypropylene (PP)

PP is a very good plastic! It is:

Tough
Does not break easy
Good with chemicals
Cheap to use People use PP to make:
Food boxes
Car parts
Toys PP costs about $1.50 to $2.50 for each kg. It is the most used plastic with 25% of all plastic parts![^2]

2. ABS Plastic

ABS is very strong. It can take a hit and not break! At Istar Machining, we use ABS a lot. ABS is good for:

LEGO bricks
Car parts
TV and phone cases ABS costs $2.00 to $3.50 for each kg. It makes up 18% of all plastic parts.[^2]

3. Polycarbonate (PC)

PC is clear like glass! But it won’t break like glass. It can get hot and still be OK. PC is used for:

Safety glasses
Medical tools
Car lights PC costs more than PP. It is $3.00 to $5.00 for each kg. It makes up 12% of plastic parts.[^2]

4. Nylon (PA6/PA66)

Nylon is very strong. It can rub on other parts and not wear down. Nylon is good for:

Gears
Car parts that move
Things that need to be tough Nylon costs $3.50 to $6.00 for each kg. It makes up 10% of plastic parts.[^2]

5. HDPE (High Density Polyethylene)

HDPE is stiff and good in the sun. It won’t break down with UV light. HDPE is used for:

Chairs for outside
Pipes
Toys for outside HDPE is cheap! It costs $1.20 to $2.00 for each kg. It makes up 15% of plastic parts.[^2]

6. PMMA (Acrylic)

PMMA looks just like glass! It’s very clear. It’s good in all types of weather. PMMA is used for:

Signs
Lenses
Clear covers PMMA costs $4.00 to $6.50 for each kg. It makes up 5% of plastic parts.[^2]

7. TPU (Thermoplastic Polyurethane)

TPU is soft and bendy. It can stretch and then go back to its shape. TPU is good for:

Phone cases
Seals to keep water out
Soft grips TPU costs $5.00 to $8.00 for each kg. It makes up 8% of plastic parts.[^2]

8. PET (Polyethylene Terephthalate)

PET is light and keeps air out. It’s what we use for soda bottles! PET is used for:

Bottles
Food boxes
Clear packs PET costs $1.80 to $2.50 for each kg. It makes up 20% of plastic parts.[^2]

9. POM (Delrin)

POM is slick. Parts can slide on it with no sticky feeling. It stays the same size when hot or cold. POM is good for:

Small gears
Zippers
Parts that need to slide POM costs $4.50 to $7.00 for each kg. It makes up 7% of plastic parts.[^2]

10. LSR (Liquid Silicone Rubber)

LSR is safe for food and bodies. It can get hot and be OK. LSR is used for:

Medical seals
Baby parts
Kitchen tools LSR costs $8.00 to $12.00 for each kg. It makes up 3% of plastic parts.[^2]

Common Plastic Materials for Injection Molding

How Different Places Use Plastic

+Packaging(30%)+Electronics(20%)+Medical(10%)+Others(5%))

Cars (35%)

Cars use a lot of plastic! They use:

PP to make bumpers
Nylon for parts that get hot
ABS for dash boards

Packs (30%)

Packs for food and stuff use:

PET for clear bottles
HDPE for milk jugs
PP for food tubs

Electronics (20%)

TVs, phones, and games use:

ABS for cases
PC for clear parts
Nylon for small parts

Medical (10%)

Doctors and hospitals use:

PC for tools that need to be clean
LSR for parts that touch skin
PET for drug packs

Real Stories About Plastic Parts

Car Bumper Story

A car maker used PP with glass in it. This made the bumper:

20% less heavy than metal
15% less cost to make
Just as strong!

Medical Tool Story

A hospital used PC to make tools. These tools:

Could be cleaned 1,000 times!
Did not break
Stayed clear to see through

Helping the Earth

Not all plastic is good for the earth. Here’s what we know:

Only 9% of all plastic gets made into new things[^3]
PET is best with 55% being made new in some places[^3]
PP is hard to make new with only 3% being reused[^3]

Why Choose Istar Machining?

At Istar Machining, we can help you pick the best plastic for your part. We use CNC plastic to make high-quality parts.

We can work with all these plastics:

PP for cheap parts
PC for clear parts
Nylon for strong parts
PET for food parts
And all the rest!

If you need plastic parts, we can also help with plastic CNC turning for round parts.

What to Do Next

Want to make plastic parts? Here’s what to do:

Think about what your part needs to do
Look at our list of plastics
Call us at Istar Machining
We will help you pick the best plastic
We will make your part just right!

Plastic Material Table

Here’s a simple table to help you pick:

Plastic	Good For	Cost	Strength	Clear?
PP	Food, Cars	Low	Medium	No
ABS	Toys, Phones	Medium	High	No
PC	Safety, Medical	High	Very High	Yes
PET	Bottles	Low	Medium	Yes
Nylon	Gears, Moving parts	High	Very High	No
HDPE	Outside stuff	Low	Medium	No
PMMA	Signs, Lenses	High	Low	Very Clear
TPU	Soft, Bendy parts	High	Low	Can be
POM	Sliding parts	High	High	No
LSR	Food, Body safe	Very High	Low	Can be

Last Words

Picking the right plastic is very important! It can make your part work the best. It can save you money too.

At Istar Machining, we know all about plastics. We can help you with:

Picking the best plastic
Making the mold
Making the parts
Making sure they work right

Call us today to start your project!

[^1]: Data from industry manufacturing reports, 2023. [^2]: Market share statistics from Global Plastics Alliance, 2023. [^3]: Recycling rates from European Plastics Association, 2023.