CN Mould & Plastic Limited
EN
#Advanced manufacturing

Injection TOOLING

With more than 20 years of comprehensive experience and expertise, our professionals provide quality mold manufacturing from concept to completion. With the support of in-house engineers, we leverage our expertise in 2D and 3D mold design. We have comprehensive and authoritative 3D surface processing knowledge, using solid model design, for medical, electronic, cosmetics, automobile, commercial machinery, and other plastic products manufacturing plastic injection mold. CN Mould & Plastic Limited has a team of experienced engineers, which can provide quick turnaround time for any mold maintenance needed.


In addition to traditional machining operations, our workshop is equipped with computer-aided functions, including:

Full set of internal mold structure.

• CNC milling, turning, and high-speed graphite milling.

• CNC countersunk machine, hole elevator, and wire cutting machine.

• CNC programming for computer-aided manufacturing.

• manufacturing mold parts and fixtures for secondary operations.


PROCEDURE IN PLASTIC INJECTION MOLD MAKING

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1. Mold Design

The mold design is based on the shape, size, material and property of the injection parts. Choose the proper mold material with good quality and property. 


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2. CNC Machining

CNC machining is a very important part of mold manufacturing. CNC machining can realize high-precision and high-efficiency parts manufacturing, which is particularly important for mold manufacturing. In CNC machining, milling, cutting, drilling and other processing methods are usually used to manufacture the molds.


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3. Precision Grinding

Precision grinding is one of the key steps in mold manufacturing. Precision grinding can help grind the individual parts of the mold and ensure its dimensional accuracy and surface roughness. It also can increase the sealing performance and abrasion resistance, and improve the mold life.

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4. Electric Discharge Machining

EDM is an efficient non-contact processing method, which can achieve metal melting and cutting through the discharge phenomenon, and is also very important for mold manufacturing. EDM is usually carried out in the mold parts with high precision requirements.EDM can improve the accuracy and surface finish quality of the mold, and reduce manufacturing and processing costs.

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5. Assembly and Mold Testing

After the mold manufacturing is completed, assembly and mold test are required. During assembly process, each parts of the mold should be checked to be accurate and fastening. During commissioning process, it is necessary to carry out injection molding test for testing the performance and reliability of the mold. 

MAKE POSSIBLE WITH CN-
Your Professional Plastic Injection Mold Manufacturer

CN Mould & Plastic Limited has a plant of 10,000 square meters for mold manufacturing and injection molding in Shenzhen and Zhongshan, Guangdong, China. Being in the industry for over 20 years and certified by IATF16949, CN team has developed all different kinds of molds, from rapid prototypes to large-scale production molds like multi-cavity, 2K, liquid silicone rubber, inserting, and our molding press up to 1,000 tons. CN Mould & Plastic Limited utilizes state-of-the-art equipments such as wire-cut, EDMs imported from Switzerland, high-speed CNC machines, CAD/CAM, and milling, drilling, and grinding machines.Our professional group of engineers and plastic injection molding experts have over 15 years in injection molding and mold making industry in adverage. CN Team can always be your reliable partner to collaborate with and our friendly team is always here to help you turn your concept into a reality.

Plastic Injection Mold Application

Injection molds can process a variety of plastic products, such as electronic product shells, toys, household items, auto parts, medical devices and so on. The following are some common injection mold processing products:


Electronic product shell: such as mobile phone, TV, audio and other electronic products shell, using high-strength, durable plastic material injection molding to meet the product appearance and performance requirements.


Toys: Injection molds produce a variety of toys of different shapes, including children's toys, educational toys, sports toys, etc. These toys can be injection molded with different materials, such as PE, PP, etc.


Household items: Injection molds can be used to produce a variety of household goods, such as plastic hangers, plastic buckets, plastic chairs, etc. These products have excellent durability and lightweight, which are very suitable for family use.


Automotive parts: Injection molds can be used to produce auto parts, such as doors, car dashboards, lights, etc. These products need to have high heat resistance, corrosion resistance and toughness to meet the requirements of the automotive working environment.


Medical devices: Injection molds can be used to produce a variety of medical devices, such as medical syringes, medical nonfat yarn, etc., which need to have good biocompatibility and durability to meet the strict requirements of the medical industry.


Plastic Injection Mold Application

Typical Tool Structure

Typical Tool Structure


1. Sprue separating area

2. latch

3. Sprue

4. Retainer pin

5. Head of bolt

6. Sprue-Stripping plate

7. Pin

8. Guide strip

9. Waterway

10. Bolt

11. Main parting line

12. Ejector pin

13. Stripper sleeve

14. Plate assembly

15. Mold cores


Typical Tool Structure

What is CNC machining
for Injection Mold Making?

CNC machining is the main production procedure for tool making. Molds are usually machined out of steel and stainless steel, but sometimes aluminum is also used. Aluminum cannot withstand the tear and wear of injection molding as well as steel, but it is a cheap alternative for small-batch injection molded parts.


The core of the tool must be able to keep its precise dimensions and feature over the course of thousands or millions of injection cycles, along with all the stress and heat enforced on them. CNC machining makes forming the metals to the required tolerances simple. At CN Mould & Plastic Limited, CAD/CAM software are implemented to produce sophisticated, perfect tool for designing and machining molds.


What is Electrical Discharge Machining (EDM)
for Injection Mold Making?

Electrical Discharge Machining (EDM) is a machining process that utilizes electrical discharges or sparks to remove material from a workpiece. It is commonly used for machining complex shapes and hard materials that are challenging to machine using traditional methods.


The EDM process involves a workpiece and an electrode, typically made of conductive materials such as copper or graphite. The workpiece and the electrode are submerged in a dielectric liquid, which acts as an insulating medium and helps facilitate the discharge process.


When an electric voltage is applied between the electrode and the workpiece, a high-energy electrical discharge occurs in the small gap between them. This discharge creates an intense heat that melts and vaporizes a tiny portion of the workpiece material. The dielectric liquid then flushes away the molten debris, and a new discharge is initiated.


By controlling the electrical parameters such as voltage, current, and pulse duration, as well as the positioning of the electrode, precise material removal can be achieved. The process is typically computer-controlled, allowing for high accuracy and repeatability.


At CN Mould & Plastic Limited, EDM is particularly useful for machining intricate shapes, thin sections, and hardened materials, such as tool steels and exotic alloys. It is commonly employed in industries like aerospace, automotive, mold and die making, and electronics manufacturing.


Injection Molding Machines at CN Available for Mold Trial

CN Mould & Plastic Limited owns more than 135 injection molding machines including vertical machines and horizontal machines. In particular, we have a set of vertical injection molding machine with horizontal injection units that suits for insert molding trials. The vertical machine structure allows ease of insert placement.


Features of Injection Molding Machine


1. Vertical clamping; horizontal injection.

2. Strong structure. Clamping force is up to 500 ton.

3. The injection base height is adjustable, leading to more flexibility in mold design.

4. Diversified oil circuit system design(semi-closed, servo or high-speed injection) to meet customers' needs.


Injection Molding Machines at CN Available for Mold Trial

Tool Steel List

BrandSteel Material No.Comparison of Standard and PropertiesHardnessHardness after Heat TreatmentProperties and Applications
AISIJISDINHBHRCHRC
ZHAOHENGS136420 Modified ESRSUS420J2 Modified ESR1.2083 Modified ESR=235-HRC46~52High purity, fine and uniform organization, excellent polishing performance, corrosion resistance and good dimensional stability of heat treatment. It can be used for mirror molds and the production of corrosive plastics and plastics adding accelerants.
S136H420 ModifiedSUS420J2 Modified1.2083 Modified
30~37No heat hardening requiredPre-hardened die steel with hardness HRC30~37, high purity, fine and uniform organization, high-quality polishing performance, corrosion resistance, good dimensional stability of heat treatment.
H13H13SKD611.2344=235-HRC48~52High toughness and good thermal fatigue performance, suitable for zinc alloy, small aluminum alloy die casting mold, plastic mold.
NAK80P21 Modified
VAR
---37~43No heat hardening requiredMirror polishing up to #8000, age hardening steel, excellent dimensional stability, excellent discharge processability and sun grain. Suitable for the production of medium mass production of simple shape, surface requirements and processing accuracy requirements of the ordinary mold such as car instrument panel, copier panel. Not suitable for the molds with Tianjin fire retardant and high corrosion requirements.
P20P20
1.2311
30~36No heat hardening requiredEconomical pre-hardened plastic die steel. Suitable for high strength die frames and molds for small and medium mass production without surface requirements.
01


=235-HRC46~52Can be hardened to HRC46~52. Generally used for mold accessories, laminates, wear-resistant blocks.
45#、50#1045-1050S45C-S50C-1.1730=235-No heat hardening requiredWith good machining and machinability, it's suitable for mold plate and mechanical accessories.
738HP20 Modified-1.2311 Modified-33~40No heat hardening required(SW318H)--Pre-hardened tempered non-forged steel, large size cross-section hardness uniformity, good welding and thermal conductivity. Suitable for small batch plastic mold production. Not suitable for the molds with Tianjin fire retardant and high corrosion requirements.
718HP20 Modified
1.2738 Modified
33~40No heat hardening required(SW718H)--Pre-hardened tempered non-forged steel, large size cross-section hardness uniformity, good welding and thermal conductivity. Suitable for small batch plastic mold production. Not suitable for the molds with Tianjin fire retardant and high corrosion requirements.
LKMLKM2344ESRH13 ESRSKD61 ESR1.2344 ESR=229-HRC48~54High purity of steel, uniform structure, excellent toughness and anti-tempering, good fatigue resistance and permeability and good mirror polishing. Suitable for small and medium-sized high surface finish mold without wear resistance requirements.
LKM S7MS7 Modified
1.2357 Modified=229-HRC52~58After ESR remelting and refining treatment, the steel has high purity, fine microstructure, excellent mirror polishing, sun grain, high wear resistance and good high temperature strength and toughness, and the hardness can reach HRC56-58. Suitable for small and medium-sized long-term production of glass fiber, carbon fiber and other reinforced plastic injection mold. Thermosetting plastic compaction die is also applied to hot stamping die and aluminum alloy extrusion die.
LKM C1100PJIS C1100P


Cu copper; High purity, excellent electrical conductivity, easy processing, low deformation. Suitable for precision spark machining electrode.
LKM2083420SUS420J21.2083=240
HRC46~52Used in hardened state; good corrosion resistance, wear resistance and polishing properties. Suitable for molds for long-term production of corrosion-resistant plastics.
LKM2083H280~32029~34No heat hardening requiredPre-hardened die steel, good corrosion resistance, wear resistance and polishing properties. Suitable for the production of small and medium-sized batch of corrosion resistant plastics.
CN2311-P20
-1.2311260~34026~36No heat hardening requiredPre-hardened ordinary plastic die steel. Suitable for high strength die frames and molds for small and medium mass production without surface requirements.
USA MATERION
Beryllium Copper Alloy
MOLDMAX HHUNS C17200-36~42No heat hardening requiredHigh strength beryllium copper alloy, excellent thermal conductivity and high strength, greatly improve injection efficiency and product appearance. Suitable for mold cores and inserts requiring rapid cooling.


Checklist for Injection Mold Trial

New Mold Validation Check List                                   Tool #: ________

No.Point to be verifiedYesNoNAComments
Processing Info
1Is Process parameter sheet available?



2Press screen (temperatures, pressures, injection speed) available?



3What's the barrel size?



4What's the melt Temperature of material?



5What's press Tonage (photo press screen with actual campling force)



6Is cooling conexion diagram available?



7Is electrical diagram (book from hot runner supplier) available?



8Is final part weight vs. Non-pack part weight available?


Final weight :
Non-pack weight:
9Ratio Press (diameter of injection cylinder, how many cylinders?)


Cylinder size:
# cylinders :
10What is the actual neumatic or hidraulic pressure used? (cores press screen) If applicable



Tooling Info
11Hardness of materials (cores, cavs, slides). Certificates and physical test at blocks



12Are cavity block properly identify at tool (engraved at the cav block and at the mold base)?



13Are all parts properly engraved at mold? (slides, lifters, ejector pins, etc)



14Are cooling lines properly identify (in-out) ?



15Is the mold free of  water/oil leaks? (verify with air)



16Does the mold has enough support bar and are properly located?



17Are the security bar properly located?



18Does the mold has 2 rings to mold handdling and properly located? (Mold must have thread holes for rings at 2 sides of mold)



19Has every zone of electrical system being review for proper functioning?



20Are the parting lines located as per DFM?



21Is part properly engraved per print?



22Does the part has date codes as per print and DFM?



23Is the weight of tool marked at mold? (engraved, paint, stamped)



24Is general tool size marked at mold? (engraved, paint, stamped)



25Has every retractil mechanism their own position sensor and conected in serie?



26Is "top" painted at the top side of the tool? (engraved, paint, stamped)



27Are the ejector bars same level as tool?



28Are center ring and nozzle size proper size?


Center ring size:
Nozzle size:
29Is the mold free ofevidence of welding, being packed, noizes or golding?



30Are the vents properly located and go thru the outside?



31Is the ejector system layout as agreed per DFM?



32Is the mold safe enough for handling in the tool room? (Review that the excess in the clamp plate is only that required by setup)




33Are spare parts from a comercial brand? (Prefered Misumi)



34Is mold documentation such as 3D and 2D prints available?



35Is the hot runner documentation avaiable? (2D/3D/sutcase/tools)



36Are the codes for spare parts available for quick buy?



37Are spring codes available and do they follow color code?



38Does mold has cover to protect mold at handdling? (bottom cover)



39Is final dimensional report and final shot available? (include runner)



40Verify that all visual characteristics marked at print are present on plastic part.






41Is the measuring fixture available?



42Are part gages available?



43Are mold photos and video available?



44Is test working properly?



45Are test photos and video available?



46Is test documentation such as 3D and 2D prints available?



47Are actual mold dimensions exactly the same as the 2D and 3D data?




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#ADVANCED MANUFACTURING
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