key point of injection mold design (1/2)

Injection molded parts design point.

1, the product produced using the injection molding process , the plastic in the mold cavity uneven cooling and uneven shrinkage and the design is unreasonable , prone to various defects in the product: Sink mark , weld lines , bubble, deformation, ejector mark, flash.

 

2 , in order to obtain high-quality plastic products, we must fully consider its structure in the design process of products, combined with the following.Analysis method to avoid defects according to the main structural features of injection molding products.

 2.1 direction and mold parting line

     At the beginning of each products designed, must first to determine its direction and mold parting lines , in order to ensure as much as possible to reduce Pulling and eliminate the impact on the appearance of the parting line .

2.1.1 determine the direction of the mold , ribs, clips and other structured products should be designed as the mold the direction, in order to avoid reducing core pulling, extend tool life .

2.1.2 Example: bumper mold direction is generally the direction of the vehicle body coordinate χ , if designed to mold the direction of the axis χ  Inconsistent, you must specify the angle at which the product graph..

2.1.3 determine the direction  , you can select the appropriate parting lines to improve the appearance and performance.

2.2  draft angle.

2.2.1 appropriate draft angle to avoid product scratch . draft angle should be greater than 0.5 degrees for smooth surface, fine  Surface greater than 1 degree, coarse surface greater than 1.5 degrees.

2.2.2 appropriate draft angle can avoid parts’ injury .

2.2.3 for the deep cavity design, requires the outer surface slope angle less than the inner surface , to ensure that no deviation when injection , to obtain a uniform thickness of the product , and to ensure the opening portion of the product density of the material strength.

 

2.3Wall thickness of products

2.3.1 certain kinds of plastic wall thickness range , generally 0.5 ~ 4mm, when the wall thickness is more than 4mm, the cooling time is too long , resulting in sink mark and other issues, should consider improve and changing the product structure.

2.3.2 The wall thickness would cause surface and sink mark.

2.3.3 products with uneven thickness would cause bubble and sink marks.

 

2.4 reinforcing rib

2.4.1 strengthen the rational application of ribs , increase product rigidity and reduce distortion.

2.4.2 stiffener product wall thickness must be less than 1 / 3 , otherwise the surface would have sink mark

2.4.3 ribs should be greater than the slope of one side of 1.5 °, to prevent ejector mark .

 

 2.5 Chamfer

2.5.1 rounded product may cause stress concentration is too small , causing cracking products .

2.5.2 rounded mold cavity is too small,may cause stress concentration , leading to the cavity cracking.

2.5.3 Set reasonable chamfer , but also can improve mold processing technology, can be directly used as cavity milling cutter R , While avoiding inefficient power processing.

2.5.4 Different chamfer may cause moving parting line should be combined with the actual situation of choosing different fillets or clearance angle .

 

  2.6 Hole

2.6.1 shape of the hole should be as simple as possible , and generally rounded.

2.6.2 consistent axial and mold the direction of the hole , core pulling avoided .

2.6.3 When the hole when the aspect ratio is greater than 2 , should be set stripping slope . The diameter of the hole should be at this time trails size ( the largest real Body size ) is calculated .

2.6.4 blind hole aspect ratio is generally not more than four .

2.6.5 the distance from the hole to the edge of product is generally greater than the aperture size.

 

2.7 injection mold core-pullingmechanism and avoid

2.7.1 When the plastic parts can not be successfully mold press release direction , pulling mechanism should be designed . Pulling mechanism of complex products can be molded Structure, but can lead to product patchwork line , sink mark and other defects, and increase the cost of shortening the life of the die mold .

2.7.2 The design of injection molding products, such as no special requirements to avoid pumping core structure . If the direction of the axial hole and tendons change, then trying other methods.

 

 

 

professional tool shop in china,refer to

www.freetech-mould.com

 

 

 

Silicone Mold Problems

 

Frequent Questions

1 . Why silicone mold appear less turning model ?

In the process of making molds adding too much silicone oil, silicone oil destroys the molecular weight silicone , so the mold will be fewer non-durable turning model such phenomena . If molding more complex patterns products come with a large hardness silicone mold , there will be fewer turning model of the phenomenon , because silicone excellent time will be very brittle , easily broken . Conversely , if you do build a product to do with a small hardness silicone mold , the result would be equally unsatisfactory . Because the silicone is too soft, it will reduce the tensile and tear strength , made ​​out of the mold will be deformed , so turning model number will be reduced. Plastic mold itself is very good quality , silicone no good or bad , only suitable or unsuitable . We should adopt appropriate size product hardness silicone to make a mold.

2  Why silicone mold have burning phenomenon ?

Because unsaturated resin and resin product added peroxide curing agent after the reaction in case of resin will produce a lot of heat, general resin curing time of 3 minutes, three minutes after going to release soon , will prevent the silicone mold burning problem

3 Why silicone mold will appear in the table dry quit phenomenon ?

Silicone mold belongs condensation silicone , which is absorbed by the moisture in the air and cured silicone in the process of making , the water evaporated , while there is no transferred amount of water, this phenomenon occurs . Solution: This phenomenon does not belong to product quality issues , but because there is no control of moisture , silica gel to enhance shelf life , shelf life of these phenomena appear long , long time using silica gel , add amount of 0.05% water ,  the problem can be solved.

4 Why silicone mold appear poor tension phenomenon ?

Because the client in the production process of the mold in order to reduce the viscosity of silicone , silicone easy to make large amounts of silica in a silicone oil is added , this will become very soft silicone that produce intolerance pulling the tear strength is reduced , Rally deterioration phenomenon resulting mold is not durable , life is short, less turning and so on.

5 Why mold will appear oil flush?

Silicone mold itself have no oil flush problem , just because during operation adds composite silicone ( silicone oil with white mineral oil complex ligand ) as white mineral oils are petrochemical products, not silicone .

6 Why mold have aging phenomenon ?

In the process of making silicone molds , we recommend our customers the best without any oil, if necessary , the amount of silicone oil added up to no more than 5 % to 10 %. Because the addition of silicone oil will destroy the molecular weight silicone too , so do not come out of the mold will produce acid , intolerant aging phenomenon.

7. Why silicone mold have surface marks , stripes, not smooth and so on ?

This phenomenon is a product or a model to be replicated no grinding or polishing sake. Because in fact the model or the product itself is not enough to smooth or perfect , so the product or model to be copied if not polished or polished , even the best silicone molds will do pretty, is not smooth enough . Another case is , when playing a release agent , no uniform brushing can also cause mold surface problem.

8  you know the usage of mold silicone?

Silicone mold is mainly used for toy and gift industry , craft industry , furniture decoration industry , figures copied , building decoration industry , resin handicraft industry , unsaturated resin crafts industry , candle craft, Plastic toy industry ,Gifts stationery industry,Gypsum gifts industry, mold manufacturing industry, Bolero industrial , simulation plant and animal sculptures, Buddhist carvings crafts products and other industries copy and mold making .

Mainly in used in toys , gifts, floral fine products for packet mode , filling mold products , glass , lighting , candles , figures copy production molds , large products , open- slice mode , relief , statues , gifts making molds , sole model , perfusion mold, sand- casting.

A variety of different uses specific operations silicone mold is also not the same , what is required to achieve the specific operation must be based on a variety of different parameters.

 How to clean

General production mold clean up our way is the use of sandblasting ,place the silicone products mold into blasting machine, blasting head is aligned with the production of silicone products mold cavity , and then gradually Sort cavity by sandblasting .

 

 

A professional tool shop in china ,with  good quality,competitive price and best service.

pls refer to   www.freetech-mould.com

 

 

 

what's silicone molding?silicone mold, mold silicone

Silicone Mold

Silicone molds are produced crafts special mold rubber, silicone is characterized by high temperature, corrosion resistance, tear resistance and strong , high simulation fine , special molds for making all kinds of crafts .

 

Silicone mold materials

Silicone is good for its environmental performance and more and more people know and understand the silicone mold , let’s start form silicone raw materials .

1 , according to the performance of raw materials, silicone can be divided into ordinary silicone and The pure silica gel

Ordinary silica also known as precipitated silica ,

Color: translucent, milky white , pale yellow , gray and so on.

Hardness : 30 °, 40 °, 50 °, 60 °, 70 ° , commonly between 40 ° -70 °.

Density :1.1-1 .12g/cm ³

Elongation: 400%

Uses: more used on phone keypad, miscellaneous items, such as middle and low conductive silicone rubber products .

pure silicone rubber Color: Clear .

Hardness : 30 °, 40 °, 50 °, 60 °, 70 °, 80 ° , commonly between 40 ° -60 °.

Density :1.1-1 .12 g / c ㎡

Elongation: 600% -700 %

Features : Because this material is good transparency , strong tensile . High cost

Usage: silicone tube, protective cover and other high need high flexibility products .

2 , according to the physical properties of silicone raw materials, can be divided into solid silicone and liquid silicone .

Solid silicone is mainly used for molded products. For example: silicone case , silicone utensils , silicone molds, silicone keys , etc., mainly used for liquid silicone extrusion products, such as silicone nipple , silicone tubes.

Insulation silicone pad , excellent heat capacity , silicone ( food-grade silicone ) resistant to 200 ℃ high temperature and long-term use , the production of raw materials meet food grade standards , through FDA food-grade test , tasteless , non-toxic , mold manufacturers in accordance with production, color, shape can be customized .

 production process

Molding form and mold parting line is very important.  first, to take the easy mode , the second is the parting line should be selected without affecting the overall effect of the product, the third is not to affect product quality , such as mold line position waterscape series too high , sealing materials and more time to mold line of products prone to cracking ; fourth step is to reduce the flow of operations , such as opening half of the mold .

In order to prevent the flow around the silicone mold, use some slice for blocking the certain area , no gap , oil smooth surface . After completion of the above work to prepare , and then on the kinds of painted plaster mold or mold release agent on Vaseline or spray , smooth product requirements with a clean cotton cloth soaked in Vaseline evenly on the mold, the mold for 30 minutes species to fully absorb Vaseline , and then a clean cotton cloth to clean the surface of the mold require bright surface ; rather have the texture of the product as long as evenly coated with Vaseline on it will be better formulated silicone tune. When the direction of the irregular silica gel formulation should be agitated to mix the curing agent and silicone sufficiently minimize pumping to maintain a vacuum of the required air -0.1Mpa within the mixed rubber , smooth product is best when the adhesive coated first layer 7-8 seconds.

With a good silicone molding should be timely . The glue in a way trickle down to the highest parts of the mold , let it flow , where the flow is not in place with a painting brush in place, if it is not only full piece molded silicone brush evenly throughout the product but also on clay . Each item of each brush at least three silica layer thickness of silica 1mm, the brush process silica required to brush after each additional layer of the cured layer , the third layer when the brush is applied to the top of a second layer layers of gauze to increase the strength of the silica gel . Entire mold silicone products based in part on the size of the different requirements of thickness control in 3-4mm, width no greater than the product width 60 mm. Start silica gel solidification time was 20 minutes.

1 , clean and dry the female die, (brushing a layer of mold release wax release agent )

 2, 500-1000 grams of silicon rubber mold ( silicone molds , rubber molds , silicone rubber , silicone ) keep well for spare ;

3 , weight certain proportion hardener ( typically 1.5-2.5 % ), put in a container, mix and stir ;

4 , depending on the situation (especially for the first layer ) by adding a certain amount of silicone  dilution. Until thoroughly mixed up , usually 3-5 minutes.

5. Silicon rubber mold ( mold silicone mold , silicone rubber , silicone ) and the curing agent mixture , i.e. the reaction at room temperature , and the release of low molecular weight alcohol , the alcohol molecules from the colloid is required under the negative pressure discharge bulbs 1-3 minutes. Also available ( depending on the tool maker’s experience ) without the aid of equipment.

6 , multi- piece mold brushing should follow inner, middle and outer while curing appropriate. Curing agent is relatively low, the reaction time is lengthened , the reaction fully , like colloids , thus curing agent is preferably within a little more than outside . When brushing until the first layer ( inner layer ) dry and then brush a second layer . Operating time 30-50 minutes , removal time 10-15 hours. Curing time 24 hours . Note brushing first , the best use mold cloth , which can greatly improve die life ( but must not use the glass fiber cloth , or likely to cause mold scrap )

7 , three-dimensional perfusion mode , generally 10-15 hours curing as well.

8 , but also of the soft mold produced coat plaster or fiberglass to support soft silicone mold Note : 1 , analog line options: Choose the location does not affect the appearance of the product ; selection position after filling easy processing ; choose mold itself is easy to dismantle location mold ; select products easily deformed position 2 , the production schedule must not rush blindly to increase the amount of hardener , otherwise it will greatly reduce the silicone mold life.

 

 

 

 

what's blow molding

Plastic blow molding technique is developing rapidly for plastic process . The thermoplastic resin obtained by extrusion or injection molding of plastic tubular parison hot ( heated or softened state ) , placed inside the mold cavity , then closed mold immediately, pour into air, blowing the plastic parison inflation and close to the inner wall of the mold cavity, cooled mold , that get all kinds of hollow plastic products.

 Technical Overview     Blow molding process during World War II began for the production of low-density polyethylene vial. In the late 1950s , with the development of high-density polyethylene birth and blow molding machines , blow molding technology has been widely used. Hollow container volume up to thousands of liters, and some have adopted computer-controlled production . For blow plastics are polyethylene, polyvinyl chloride, polypropylene, polyester, etc. , resulting into the empty containers are widely used in industrial packaging containers.

According to the production method of the parison , blow molding and extrusion blow molding can be divided into the injection blow molding, a newly developed multi-layer blow molding and stretch blow molding.

 

 Prospects    In recent years , with the development of a variety of functional beverages and wine packaging market , a variety of multi-layer co-injection - blow molding technology become a hot market .

Flexible step production technology

Injection stretch blow molding hollow articles having uniform thickness, good dimensional stability, light weight , high strength , etc., and therefore a very wide range of applications . As the injection stretch blow container craft production mostly PET, PP, PE, PVC and other materials as raw materials, and the use of these raw materials to produce bottles with light, portable, non-toxic , transparent, unbreakable , good barrier properties , etc., making it more and more as an alternative medicinal bottles were used in carbonated drinks, juice drinks , water , edible oil , alcohol , cosmetic products, pharmaceuticals and other industries packaging.

Injection stretch blow a two-stepprocessing method and one-step process . One step from raw material to complete the entire container molding process on a single device. Two-step process from the raw materials needed to complete the two devices to products molding process . Two-step method is mainly suitable for mass production , and flexibility, both equipped with a multiple injection blow molding machine can also be equipped with more than one injection blow molding machine . Of course, this should be based on production to match the main injection machine and blowing may be.

 

 

 

what's color mold? double shot molding two shot mold double injection

Color mold : two on the same plastic injection molding machine , a two- molding, but the product just only in one mold die . In general, this is also called double injection molding process. it is usually done by a mold , and need specialized color injection molding machine . Color mold growing popularity on the market today , it can make the appearance of the product is more beautiful from the process, easy to change colors and no no painting, also expensive and high technically demanding .

1 two female molds are different , each forming one kind of products, and the two male molds are the same.

2 before the mold, the mold in the center of the rotation after 180o, must match. This inspection must be done during mold design , this points have high demand for the mold base positioning  process.

3 The total thickness of the front plate plus A plate must be not less than 170mm. Please carefully review the reference data of the injection molding machines. for example, the maximum and minimum thickness of the mold, KO -hole distance etc.

4 the gate of three plates mold preferably designed to automatically release action. Particularly pay attention to the gate release of soft part..

5 when design the second injection of the female die , in order to avoid secondary mold insert ( or rub ) the first part with good product molding, can make some clearance . However, the intensity must be carefully considered . During injection ,if there will be a big injection pressure , it will cause deformation , resulting in flash problem in the second injection ?

6 during the injection , the first injection molded product may be slightly larger size , so that it can be formed in the second well tightly, in order to achieve the effect of sealing compound .

7 pls note that in the second injection , the plastic flow will impulse the first product and cause part deformation ? If there is the possibility, must find ways to improve .

8 Before A, B plate clamping , pay attention to the mold slider or lifter ,if they will be reset and the crushed product ? So , we must find ways to make the A, B plates first clamping , then make the slide or lifters reset second.

9 the water of two female molds and the male mold transport as fully and balance as possible

10 99% of the injection molded hard plastic case is the first part of the product , and then injection molded soft part . Because soft part have deformation problem .

 

 

Profession Tool Shop in China

Free Technology Co.,Ltd(www.freetech-mould.com)

was established in 1993, being specialized in mould design and manufacture. At present, Free tech is located in Shajing,Bao‘an, Shenzhen, has a factory of 8,000 square feet and more than 300 employees, including 20 engineers,we use UG,Pro-E,AutoCAD,Matercam and Catia as our CAD software,and mould managment system, passed ISO9001:2000 quanlity assurance system in 2005.

The company owns a wide range of advanced equipments, for example: Fanuk high speed CNC from Japan,3200mm CNC milling center, 3500mm (CNC) EDM machine, precision wire-cutter,1200mm hole-drilling machine,1600-ton plastic injection molding machine, Japanese automatic 3D scanner,Mitutoyo coordinate measure mahine,Mitutoyo projector,etc.....

For over 20 years,Free tech has made varieties of moulds for famous companies. They included automobiles for HONDA、TOYOTA、Nissan, Ford, air conditioner for DAIKIN, electrical tools for Panasonic,washing machine for HITACHI, TV for 3 Bird,monitor for DELL,Acer,etc,80% of moulds are exported to USA, UK,France,Germany,Sweden,Spain and Japan etc.....

Our company have insisted on management theory of “Customer Centered, Based on practice, Develops on quality & reputation”. We supply our customer high quality mould with reasonable price. We are looking forward to your visiting our company and cooperating with you sincerely.

Free technology is a professional mold manufacturer specializing in mold research and development.Over the past 20 years, our business has spreaded into the following fields: --Part Research & Design --Plastic Mold Manufacture & Injection Process --double color mould machining --Precision Component Machining --Die Casting Mold Manufacture--Rubber & Silicone Part--blow mold and metal part Our products has been distributed into USA, UK, Ukraine, UAE,Canada, Russia, Italy, New Zealand, Japan,Australia and so on.....

Free-tech mold has gained good feedback from our customers,and has established a customer base. However, one of our business strategy is to develop new customers and to give our best servivce to more companies. If you have any inquiry on molds or parts, please feel free to contact us , we will make your design into the perfect actual products. You are welcome to visit our plant to get more information about us.

 

 

development of automobile and motorcycle mold in China

According to reports , automobile, motorcycle industry has an annual demand of more than 450 million molds , and our country large precision mold manufacturing capacity is not enough , China's current high profile car cover mold almost dependent on imports , and medium-sized interior and exterior trim pieces of plastic injection mold is also a great demand . Development of large-scale high-tech precision automobile, motorcycle cover mold and medium-sized interior and exterior trim plastic mold is an important task in the future of the automotive, motorcycle mold.

In China 's mold market , the development of the automobile mold is a top task. Because automobile and motorcycle industry is one of the five pillar industries of the national economy in China .From the economic development law, China's automobile and motorcycle industry into the " economic take-off " stage , so the production and sales , will inevitably bring about strong domestic economy , Auto mold to a huge market .

According molding material web is understood that with the rapid growth of China's automobile, motorcycle exports, plastic injection molds and metal instead of wood , make plastic mold in the automotive and motorcycle industry increased demand , especially new materials and new molding technology development , plastic products such demand in the automotive, motorcycle industry is increasing.

Auto mold -related research reports

2013-2018 domestic automobile mold industry forecast market size and depth profiling report

November 2013

2013-2017 automotive mold industry private equity business plan

China auto mold manufacturing industry investment strategy and depth of research and consulting reports 2013-2018

Chinese automobile mold industry market research and trends forecast report 2013-2018

In a certain extent, automobile, motorcycle plastic products can reflect the amount of a country's level of car and motorcycle industrial development. For example : Germany per vehicle on average use of plastic products has reached nearly 300 kilograms , accounting for about 22% of the total consumption of materials, automobile , motorcycle plastic parts is the largest country in the world uses . The average use per vehicle in Japan has reached about 100 kg of plastic , but they are the instrument panel and other interior trim parts used in all plastic products.

Currently, the automobile , motorcycle plastics applications have been developed by the ordinary decorative pieces to the structure, functional pieces . The use of plastic materials has also been extended to the ordinary plastic with high impact resistance even better composite or plastic alloy , and can appear , along with plastic material and improve the technology and process of forming , plastic products in the automotive, motorcycle application of the car industry will become more common, will inevitably lead to large-scale development of automobile and motorcycle mold.