What factors do injection molders need to consider before tooling?
Before planning injection mold tooling, injection molders need to consider the following factors:
- Product design specifications: Assess the feasibility and requirements of the design.
- Material selection: Evaluate the suitability of molding materials for the intended part, such as the shrinkage rate, flow rate, and crystallinity of the molding material.
- Part complexity: Determine the complexity of the part and its manufacturability.
- Production volume: Estimate the expected quantity of production.
- Cooling requirements: Consider the necessity for special cooling materials or techniques.
These are critical considerations for building injection molds cost-effectively and ensuring their longevity in service.
Are injection molds expensive?
Typically, we use hardened or pre-hardened steel, aluminum, or beryllium-copper alloys to fabricate plastic injection molds. The hardened steel molds are more costly due to the tool steel and heat treatment costs, but they offer superior durability and wear resistance after machining.
Many steel molds can process over a million pieces throughout their lifetime. Pre-hardened steel molds offer a less costly and less wear-resistant alternative for smaller quantities.
On the other hand, aluminum molds can be significantly cheaper and have a fast turnaround; typically, we use them for prototype tools. They are usually not appropriate for high-volume production or products with tight dimensional tolerances.
Therefore, you can select the appropriate injection mold type accordingly.
Engineering & Plastic Product Development
AMSL Tooling Room
Engineering
The engineering department is vital for the success of custom plastic injection molding and the quality of final products. Our experienced designers manage various aspects like mold geometry, material selection, and ensuring efficient production of high-quality products.
Our skilled designers are proficient in UG, Pro-E, Solidworks, and other software. We help clients turn design concepts into real plastic components using advanced CAD/CAM/CAE tools. We work closely with clients to ensure high-quality injection molds, focusing on efficient design for easy maintenance and cost-effective production. This includes everything from choosing materials to constructing molds, setting up cooling channels, air venting, and mechanical actions.
We accept a variety of CAD software and drawing formats, such as:
- Catia
- Pro-E
- Solidworks
- We prefer professional file formats like UG, STEP, IGS, and x_t, with a strong preference for STEP.
How does an injection mold work?
An injection mold is a tool used for plastic injection molding, so some people also call it injection moulding dies. Its working principle is as follows:
- Initially, resin feeding occurs, with the feeding system feeding granules into the screw barrel of the injection molding machine.
- Subsequently, heating and melting take place as the screw sends the plastic material for melting.
- As a result, pressure increases as the screw rotates, pushing molten plastic into the mold nozzle.
- At the same time, the mold fills with molten material, while the cooling system absorbs heat, causing the plastic to cool and solidify rapidly.
- Once the plastic fully solidifies, demolding and ejection happen: the cavity and core sides separate, ejecting the molded part. The screw of the injection molding machine then rotates, and the injection process begins again.
- Ultimately, cycle repetition is key: the injection mold repeats the production process in cycles to produce plastic pars.
Through precise control of temperature, pressure, and speed at each stage, injection molding achieves accurate shaping of plastic parts in various shapes and sizes. Additionally, different injection molds can be used as needed to produce a variety of products.
The following are the shrinkage ranges of several common plastics:
| Material | Shrinkage Rate (%) |
|---|---|
| PP | 1.50% |
| PP+10%GF | 0.7~1% |
| PP+30%GF | 0.4~0.7% |
| PP+T20% | 1.0~1.5% |
| ABS | 0.50% |
| PS | 0.50% |
| PC | 0.50% |
| HIPS | 0.50% |
| PC+ABS | 0.50% |
| POM | 2% |
| HDPE | 1.50% |
| PA | 1.20% |
| PMMA | 0.50% |
| PBT+30%GF | 0.50% |
These shrinkage rates are general guidelines. Actual rates may vary based on material, processing conditions, and other factors. Adjustments should be made during design and manufacturing based on specific needs and experience.
What is the lifespan of an injection mold?
The lifespan of an injection mold, also known as mold life or output, is primarily determined by the number of qualified products produced before the mold fails. This is commonly referred to as the service life of the mold. According to the Society of the Plastics Industry (SPI AN-102-78), molds are classified into five major categories:
1. SPI Class 101 Molds: These are considered long-life precision injection molds, with a production life of ≥ 1 million times.
2. Class 102 Molds: With a lifespan ranging from 500,000 to 1 million times, these molds are typically used for mass production.
3. Class 103 Molds: Medium-volume injection molds, with a lifespan of 100,000 to 500,000 times.
4. Class 104 Molds: Intended for small-batch production, these molds have a lifespan of under 100,000 times.
5. Class 105 Molds: Designed for single-piece production, prototypes, or test molds only, with a production life of less than 500 times. All other extras are optional.
So the lifespan of an injection mold depends on its classification, ranging from precision molds that can last over a million cycles to molds suitable for single-piece production or prototypes.
FAQ
How do I request a quote for an injection molding project?
To get a quote for an injection molding project, you will need prepare the information below:
molding material datasheet; product design drawing (2D & 3D)
;production volume
quality standard; tooling cost; and other requirements ( such as secondary processes and assembly)
How do I choose the right injection molder for my project?
When selecting an injection molder, consider factors such as the machine’s capabilities, production volume requirements, quality standards, lead time, and the molder’s experience with similar materials.
What is injection mold tooling?
Injection mold tooling is a type of mold, that uses an injection molding machine to melt the plastic resin and shape the parts to specification.
What does an injection molder do?
The injection molder operates injection molding machine to production plastic parts. Their main responsibility is setup molds; adjusting molding parameter;monitoring production and ensuring the molding parts quality.
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