Frequently asked questions

Poor appearance:

Air bubbles: During the injection process, gas may be trapped in the plastic, forming bubbles, which are usually caused by incomplete melting of the plastic material, poor mold venting, etc.
Burrs: Insufficient mold clearance, uneven plastic flow, etc. may cause burrs on the product surface.
Indentation: Improper mold design, excessive injection pressure, etc. may cause dents or indentations on the surface of plastic products.
Scratches: Wear on the mold surface, foreign matter entering the mold, etc. may cause scratches on the product surface.
Color difference: Uneven mixing of plastic materials, improper injection temperature control, etc. may cause color difference on the product surface.

Poor size:

Shrinkage: The plastic shrinks too much during the cooling process, which may be caused by insufficient cooling time, improper mold temperature control, etc.
Diffusion: Plastic flows too quickly during injection, which may cause the product size to expand.
Cracking: Plastic products may develop tiny cracks due to rapid shrinkage during the cooling process.
Warping: Uneven cooling during the injection process may cause the product to deform or warp.

Poor structure:

Weld line: The place where two or more molten plastic flows in different directions meet, forming a weld line, which may reduce the strength of the product.
Short Shot: Insufficient plastic injection, which may result in product defects such as incomplete parts or voids.
Cracks: Too fast plastic cooling, excessive injection pressure, etc. may cause cracks inside or on the surface of the product.
Settling: Uneven mold filling, excessive plastic shrinkage, etc. may cause the product to have concave or sunken areas.

Malfunction:

Leakage: There may be defects in the structure of the product during the injection process, resulting in the plastic product being unable to be effectively sealed, causing leakage.
Fracture: Plastic products may break due to excessive internal stress, insufficient strength, etc.
Deformation: Plastic may deform due to internal stress during the injection process or after cooling.
Poor assembly: Plastic products may be difficult to assemble correctly due to inaccurate dimensions, poor structure, etc.

Surface defects:

Adhesion: During the plastic injection process, improper adhesion to the mold surface may result in an uneven product surface.
Cracks: During the injection process, the plastic is subjected to excessive stress, which may form tiny cracks on the surface.
Bubbles: Air or gas may be trapped inside the plastic, forming bubbles that affect the surface quality of the product.
Atomization: Sol atomization may occur during the plastic injection process, resulting in atomization on the product surface.
Solving these problems requires adjusting injection parameters, mold design, material selection, etc. to ensure that the quality and performance of plastic injection products meet the requirements.

The shrinkage of plastic refers to the percentage of dimensional change of plastic materials due to temperature changes during processing. Shrinkage is usually expressed as a percentage and measures the extent to which a plastic material shrinks during the cooling process.
The following are approximate shrinkage ranges for some common plastics:
Polyethylene: PE for short
High-density polyethylene (HDPE): about 1.5-3.0%
Low-density polyethylene (LDPE): about 1.5-3.0%
Polypropylene: PP for short, about 1.0-2.5%
Polyvinyl Chloride (PVC):
Rigid PVC: about 0.2-0.8%
Flexible PVC: about 1.0-2.5%
Polystyrene: PS for short
Polystyrene foam (EPS): about 0.5-3.0%
Ordinary polystyrene: about 0.3-0.6%
Polyurethane: PU for short, about 1.0-2.0%
Polyester: PET for short, about 0.1-0.8%
Polycarbonate: PC for short, about 0.5-1.5%
Polyoxymethylene (POM): about 1.5-3.0%
Polytetrafluoroethylene (PTFE): about 5.0%
Nylon:
Nylon 6: about 1.5-3.5%
Nylon 66: about 1.0-2.5%
These shrinkage values are estimates and actual shrinkage may vary slightly depending on process, composition and conditions. It is recommended to make appropriate adjustments and tests according to the material characteristics and process parameters in the specific process to obtain more accurate shrinkage data.

The density of engineering plastics is usually expressed in grams per cubic centimeter (g/cm³) or grams per milliliter (g/mL).
The following are the density ranges of some commonly used engineering plastics:

Polyethylene (PE):
High-density polyethylene (HDPE) has a density range of approximately 0.94-0.97 g/cm³.
Low-density polyethylene (LDPE) has a density range of approximately 0.91-0.94 g/cm³.

Polypropylene (PP):
The density of polypropylene ranges from approximately 0.89-0.91 g/cm³.

Polyvinyl chloride (PVC):
The density of PVC ranges from about 1.3-1.6 g/cm³, with different densities available depending on how it is processed.

Polystyrene (PS):
The density of polystyrene ranges from approximately 1.04-1.06 g/cm³.

Polycarbonate (PC):
The density of polycarbonate ranges from approximately 1.2-1.3 g/cm³.

Nylon (PA):
Nylon's density ranges from approximately 1.1-1.15 g/cm³, depending on the type.

Polyamide-imide (PAI):
The density of PAI ranges from approximately 1.4-1.5 g/cm³.

Density is one of the important physical properties of engineering plastics, which can affect the weight, dimensional stability and other characteristics of the product. Different types of engineering plastics have different densities due to their different molecular structures and manufacturing methods.

When you are ready to hire a plastic mold manufacturer, asking smart and specific questions can help you determine the right factory for your needs and establish a successful partnership. Here are some key questions you can ask:

Manufacturing capabilities and experience:

a. How many years of experience do you have in plastic mold manufacturing?
A: Qili has more than 40 years of experience in mold manufacturing.
b. Can you provide past mold making cases and reference customers?
A: Qili mainly develops various plastic precision molds for plastic molding processing, such as cosmetic containers, mechanical parts, plastic gears, 3C mobile phones, electronic products, stationery and wire wiring equipment.

Mold Design and Engineering Capabilities:

a. Can you provide mold design and engineering services?
A: We provide one-stop service for plastic products, from plastic mold design, manufacturing, verification to shipment, we have professional equipment and an experienced team.
b. Can you optimize the product design I provide to achieve better production efficiency and product quality?
A: Qili has accumulated more than 40 years of experience in plastic mold development. It has a professional mold team and equipment from design, manufacturing, verification to shipment. It has gone through more than 3,000 sets of molds, from OEM to ODM. It continues to improve and learn, providing customers with the information and suggestions they need during development, greatly reducing development costs and time.

Balance between strengths:

Production capacity:
a. Can it meet our production needs? Such as output, delivery time, etc.
A: Calculate the number of cavities required for the mold based on the product demand, in order to achieve the customer's goals as quickly as possible.
b. Can you handle large orders and guarantee product quality?
A: Qili can manufacture multi-mode and multi-cavity molds. Problems that can be solved on the mold will never be left until the injection, which greatly saves labor costs.

Quality Control and Inspection:

a. What are the quality control standards and processes?
A: Qili has obtained ISO9001 certification and has implemented the concept of quality in every partner. We firmly believe that quality is made, not tested. We conduct trial production for reliability testing before formal production, and monitor each process at all times through incoming material inspection, first piece inspection, and process inspection. The quality assurance department is equipped with various testing equipment and calibrates them regularly.
In terms of quality management, we also face every abnormality with an honest and responsible attitude, reduce customer losses as quickly as possible, and learn from experience to continuously improve and pursue excellence, with improving customer satisfaction as the highest criterion.
b. Do you provide mold testing and modification services?
A: Yes. Qili provides T1~TN mold trial and modification until it meets customer requirements.

Warranty and after-sales service:

a. How long is the warranty period?
A: For all molds made by us and subsequently mass-produced by us, we provide a permanent mold warranty.
b. Do you provide after-sales maintenance and technical support?
A: The mold is the most important part of plastic injection. The healthier the mold is, the better the yield and quality of the products produced will be, and the longer the mold life will be. Like cars, molds require regular maintenance to maintain a healthy state. If the damage during use can be reduced, the mold life can be extended. After the mold has been used for a certain number of times, it will also affect the health and usability of the mold, so regular maintenance is required. However, mold maintenance is not just a simple wipe with a cloth. The mold parts need to be disassembled for complete maintenance. We will use environmentally friendly dry ice for cleaning operations, 360 degrees without dead ends to completely clean the mold without damaging the mold and extend the mold life.

Confidentiality Agreements and Contractual Clauses:

a. Can a confidentiality agreement be signed to protect intellectual property rights?
A: Yes. In order to protect the intellectual property rights of customers, Qili takes confidentiality measures from order acceptance to research and development to mass production to prevent product drawings and products from being leaked.
b. Can you provide a standard contract template for review?
A: Yes. Qi Li can provide confidentiality clause contracts for customers to review, and provide compensation clauses to make both parties binding and give you greater peace of mind.

1. What materials are commonly used to make plastic molds? What are the characteristics?

A: Materials commonly used in making plastic molds include:
1. Introduction of Plastic Mold Steel
(1) SKD61 Hitachi: hardness range HRc50-52, features: high toughness, good biting, high wear resistance, can be nitrided and heat treated, suitable for die-casting aluminum molds, mold cores and inserts.
(2) BPM HHH (hot forging): hardness range HRc36-40, features: German material, high hardness, high polishing, nitridable, suitable for mold steel with high polishing requirements.
(3) 2311(2738): Hardness range HRc29-32, Features: Same as P20, higher cleanliness, German material, can be nitrided, suitable for general requirements of large molds, high toughness and polishability.
(4) P-20 (cold forging steel): hardness range HRc29-32, features: general grade plastic mold steel (not suitable for biting), can be nitrided, suitable for mold steel with general requirements (suitable for templates).
(5) P-5: Hardness range HRc28-30, features: can be bitten, can be nitrided, suitable for medium and large plastic products, suitable for all kinds of plastic molds and mold bases.
(6) P-3: Hardness range HRc26-28, features: can be bitten, can be nitrided, suitable for general small-scale production plastic molds.
(7) P-1: Hardness range HRc15-18, features: can be bitten, can be nitrided, suitable for male and female molds of large plastic molds, suitable for mold bases of various molds.
(8) S45C: Hardness range HRc2-10, Features: Suitable for mold base, can be nitrided, suitable for general purposes.

2. Pre-hardened steel introduction
(1) NAK80 Datong: hardness range HRc36-45, features: good polishing, good EDM, good etching, nitridable, suitable for mirror polishing molds and cosmetic molds.
(2) FDAC Hitachi: Hardness range HRc38-44, Features: Good machinability, excellent strength at high temperature (not suitable for discharge), can be nitrided, suitable for plastic mold cores and accessories.

3. Stainless steel introduction
(1) 2083: Hardness range HRc45-52, Features: General corrosion resistance and polishability, can be nitrided and heat treated, can be used for cosmetic molds.
(2) 2083 38°: Hardness range HRc36-40, Features: Cost saving and fast delivery, can be nitrided and heat treated, can be used for cosmetic molds.
(3) M303: Hardness range HRc45-52, Features: Same as STAVAX, high corrosion resistance, can be nitrided and heat treated, can be used for cosmetic molds.
(4) M333: Hardness range HRc45-52, features: high polishing, high corrosion resistance, high clarity, high toughness, can be nitrided and heat treated, suitable for high-demand molds (optical lenses, mobile phone cases).
(5) STAVAX420: hardness range HRc50-54, features: low temperature tempering, good polishing, good corrosion resistance, can be nitrided and heat treated, suitable for cosmetic molds

The main characteristics of these materials include:
High hardness: can ensure the wear resistance and long-term stability of the mold.
Good heat resistance: Suitable for the needs of high-temperature plastic molding process, able to withstand high temperature and high pressure.
Good corrosion resistance: It can prevent the mold from being corroded by plastic materials and extend the service life of the mold.
Dimensional stability: The material has stable dimensional characteristics, ensuring the accuracy and consistency of molded products.
Easy to process: capable of precise cutting, milling and EDM processes.
Cost and Weight: Cost, mold weight, and required dimensions need to be considered when selecting materials.

2. What molding technology is used, such as CNC machining, EDM, etc.?

A: Design and planning:

Determine the design requirements of plastic products, including shape, size, material, etc. And carry out preliminary design and planning of the mold according to the design requirements.

Making 3D mold flow analysis:
Use computer-aided design (CAD) software (3D) for mold flow analysis to ensure that the model meets the design requirements and make appropriate modifications and optimizations.

Mold material selection:
Select appropriate mold materials such as steel, stainless steel, aluminum alloy, etc. based on factors such as plastic product characteristics, production requirements and budget.

CNC machining:
The selected mold material is cut and processed using computer numerical control (CNC) machine tools, and the shape and structure of the mold are cut out according to the 3D model.

EDM machining:
Mold components that require high precision and complex shapes are EDM machined to achieve the required accuracy and surface smoothness.

Assembly and commissioning:
Assemble the processed mold parts, check the mold's adaptability and operation, and make necessary adjustments and corrections.

Mould trial:
Conduct mold trials, inject plastic materials into the mold, test the molding of the product, and make necessary adjustments and corrections to ensure that the product meets the design requirements.

Production and mass production:
After confirming that the mold can operate normally, mass production of plastic products is carried out, and continuous plastic product production is carried out using the mold.

Maintenance and repair:
Regularly perform mold maintenance and repair and update when necessary to ensure the long-term use and quality of the mold.

These steps constitute a comprehensive plastic mold making process, and each step requires precise, careful and professional operation to ensure that high-quality plastic products are finally produced.

1. 2D or 3D drawings of the product or the actual product entity
2. Product material (if you don’t know the required material, our company can provide suggestions)
3. Required quantity and batch size
4. Surface processing requirements (bright surface, matte surface, textured surface)
5. Dimensional tolerance
6. Assembly requirements
7. Packaging
8. Number of mold cavities
9. Casting location and method
10. Other special needs

1. Mold cost
According to the product's appearance requirements, dimensional precision requirements, and then based on the annual production volume, the number of cavities required for the mold, pouring method, ejection method, etc.

2. Raw material costs
According to the product requirements (fall resistance, weather resistance, transparency, toughness, anti-slip, etc.), evaluate the corresponding materials and colors. The price of each material is different.

3. Injection molding cost
Calculate the cost based on the number of mold cavities, the time required for injection molding, and the tons of injection molding machine required (the more mold cavities, the higher the production efficiency and the lower the molding cost, but the more mold cavities, the lower the injection cost, and the higher the mold cost, and vice versa)

4. Surface coating
The required color is made according to the required product. Surface treatment such as painting, electroplating, printing and adding patterns are all included in the cost.

5. Assembly Packaging
Calculate the time, labor and packaging costs required based on product parts and assembly processes

6. Logistics and transportation
Calculated based on the size, weight and volume of the product and the country or city it arrives in

If it is a single process, it takes7-20 daysIf the process is complicated, the working hours must be calculated separately, and the number of days required is calculated based on the number of mold cavities * cycle * final process.

If you need a quote for a product, please contact Qili 04-25272790 Extension33, or MAIL
Domestic business MAIL: sales@chiilee.com
Overseas business MAIL: sales@shellmakeup.com

1. Parts Assembly
2. Ultrasonic welding
3. Ultrasonic melting
4. Printing and labeling
5. Finished product testing
6. Packaging
7. Inspection
8. Shipping (logistics can choose the appropriate logistics provider according to the arrival area)

Qili can produce in small batches. The lowest MOQ is based on the number of holes * cycle * 24 hours
For example, the cycle of one mold and one hole is 35 seconds, and 24 hours is 86400 seconds.
86400∕35=2469. That is, MOQ is 2469 PCS
For example, if the cycle of one mold and two holes is 35 seconds, it is 86400/35*2=4938, that is, the MOQ is 4938 PCS
If the minimum order quantity does not reach the minimum MOQ, we can make a small batch according to the quotation.

#1 Polyester (PETE or PET): Commonly found in beverage bottles and food containers. Recyclable, but avoid reuse.

#2 High-density polyethylene (HDPE): Commonly found in bottled detergents and shampoo bottles. Recyclable and widely reused.

#3 Polyvinyl chloride (PVC): Commonly found in water pipes and plastic packaging.

#4 Low-density polyethylene (LDPE): Commonly found in food packaging bags and plastic films.

#5 Polypropylene (PP): Commonly found in food boxes and bottle caps.

#6 Polystyrene (PS): Commonly found in foam plastics and food boxes.

#7 Others: Includes various other plastics, such as waterproof coatings and multi-layer composites. Recyclability depends on the specific material.

Even if there is a recycling symbol, actual recycling capabilities and regulations may vary by region. When sorting your waste, you should carefully follow your local recycling guidelines.

There are some important differences between 3D printing and traditional plastic mold injection processes in terms of manufacturing methods, material selection, production speed and cost.

Manufacturing method:
3D printing: 3D printing is a manufacturing method that builds objects by stacking materials layer by layer. This manufacturing method offers a high degree of freedom and can produce complex geometries without the use of molds. Plastic mold injection: This process uses a metal mold. The plastic material is heated and injected into the mold, then cooled to form the shape.

Material selection:
3D printing: 3D printing can use a variety of materials, including different types of plastics, metals, ceramics, etc. The choice of materials is wide and can be adapted to the requirements of the specific application.
Plastic mold injection: Traditional injection molding usually uses a specific type of plastic, usually granular raw materials.

Production speed:
3D Printing: 3D printing is typically relatively slow, especially when making large or densely packed parts. This depends on the construction time between layers.
Plastic Mold Injection: Injection molding can usually produce a large number of parts in a short period of time, especially when using a high-speed injection molding machine.

cost:
3D printing: 3D printing is generally suitable for small batch production and complex geometries, but the material cost and process time are higher.
Plastic Mold Injection: Although the initial cost of making the mold may be high, the cost per part is usually lower in large-scale production.

3D printing and plastic mold injection each have their own advantages and applicable scenarios. 3D printing is suitable for rapid prototyping, small batch production and complex geometric shapes, while plastic mold injection is more suitable for mass production, especially when there are requirements for rapid and mass production in terms of cost and production speed.
3D printing photos provided by Taiwan Baoming Freedmake professional 3D printer

Injection, extrusion and blowing are three different processing methods in the plastic processing process. Each method has its own unique characteristics and application areas:

Injection Molding:Injection is a process of heating and melting plastic and then injecting it into a mold to form it. The plastic pellets are heated and melted, then injected into the mold cavity by the injection machine, and finally cooled and solidified into shape. This method is usually used to produce plastic products with more complex molding and higher precision requirements, such as plastic casings, electronic parts, automotive parts, etc.

Extrusion:Extrusion is a process of heating and melting plastic and then squeezing the plastic through an extruder into a continuous plastic product with the desired cross-sectional shape. For example, plastic tubes, sheets, films, etc. can be produced through the extrusion process. The extrusion process is suitable for continuous production of relatively simple and long plastic products.

Blow Molding:Blow-up is a process in which plastic is heated and melted, placed in an inflatable mold, and inflated into shape using air pressure. This method is usually used to produce hollow plastic products such as plastic bottles, containers, toys, etc. The blow molding process can be divided into two main types: injection blow molding and extrusion blow molding.

Injection, extrusion and blow molding are three common plastic processing methods. They are different in processing, applicable products and process characteristics. It is very important to choose the appropriate processing method according to the specific product design and requirements.

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