Injection moulding Design

There are two areas of consideration in designing for injection moulding

Production Considerations

Plastic Injection moulding is a heat process and plastics are poor conductors of heat, that is to say it takes a relatively long time for plastic parts to cool down. With this in mind the aim should be to keep sections of parts as thin as possible, this will not only mean shorter moulding cycle times but also less material content.

Strength – If the part needs some strength this can be achieved by the addition of ribs rather than thickening of the section. With plastics, thicker sections do not necessarily mean stronger parts, in some instances beyond a certain thickness the part can become more brittle due to the resulting lack of flex.

Material– Another consideration is choice of material type and grade. Thermoplastics can range in price from just over £1 per kg for basic polyolefins up to £25 per kg and beyond for PEEK and other specialised polymers. By designing strength into a part it may be possible to use a cheaper material but sometimes the reverse can be true and advice should be sought from the moulder.

The price of polymers is also governed to a certain extent by the amount purchased so some benefit may be gained by using a grade already used by the moulder. Be guided by the moulder rather than sticking rigidly to a specified grade.

Eliminate Assembly– If a number of parts are required, and especially when converting from metal or a different production method, look at the possibilities of combining two or more parts into a single moulding so eliminating assembly. It is often possible to produce complex single mouldings that would not be possible with a different method of production. In a similar vein, where assembly is required every effort should be made to make this as simple as possible with the use of snap-fits, for example.

Injection Moulding
Injection Moulding

Tooling Considerations

Combining Parts Injection mould tooling is relatively expensive but it is not always correct to assume that it is only suited to long production runs. If it is possible to combine a number of parts into a single moulding, for example, then the cost of assembly and possible other ancillary parts can be saved making shorter production runs economical.

Keep it Simple– The simpler the mould tool the lower the cost. If possible avoid holes in side walls of parts, undercuts and other complex features. The mould tool can then be what is referred to as straight open and close. If the part does need side holes, for example, then these can either be moulded in which would require side movements in the mould tool, or a secondary operation will be necessary. Which approach is adopted will depend on anticipated quantities of the part – the higher the number of parts required the more economical it is to have the features produced by the mould tool rather than as a secondary operation.

The same rule applies to threads. Internal threads can of course be tapped afterwards but the usual method is to have them moulded in. This can be achieved in two ways, either with hand loaded cores or with auto unscrewing in the mould tool. The former requires operator intervention during the moulding process so adding to the part cost whereas the latter means the mould tool can be run fully automatically but will mean a higher tooling cost at the outset.

Multiples– To reduce both total tooling and part costs where a number of similar parts are required in equal quantities and in the same material, it may be possible to produce a family tool, i.e. all the parts moulded in a single cycle from a single tool. Also, where large quantities of a part are required, a multiple cavity tool could be used, i.e. two or more of the same part produced in a single cycle. Although the tooling cost would be higher than for a single impression tool, the part price will be lower so making it cost effective. The moulder can advise on the optimum configuration.

Conclusion

There are a number of factors that impact upon part and tooling cost: material selection, section of part, complexity of design, etc. What is certain is that the further down the design/production cycle you are the more costly any alterations become. Therefore, it is advisable to get the initial design right for injection moulding and to this end you should involve your injection moulder at the very early stages of the project to ensure correct design and material selection for the given application.

Plastic molding process

Plastics are synthetically made non-metallic compounds. It could possibly be molded into many types and hardened for commercial use. Plastic Mould products could possibly be observed everywhere. Illustrations are jars, protective caps, plastic material tubes, grips, toys, bottles, cases, accessories, kitchen area utensils collectively with a terrific offer more.

The basic idea in Plastic Mould is inserting molten fluid plastic material in to a ready shaped mold, for example the mold of the bottle. It could possibly be then permitted to cool, and then the mold could possibly be eliminated to reveal the plastic material bottle.

Plastic Mould could also custom-mold a broad range of plastic material products including: garden pots, cabinets, business office trays and boxes, barriers, barricades and site visitor’s signage and displays for product and marketing and marketing promotions.

If you are preparing to go into Plastic Mould business, you really should earliest know the many processes. Choose from the Plastic Mould method that fits your budget, your expertise, as well as your resources. Right listed here are basic definitions of many methods of Plastic Mould.

Plastic Molding Process
Plastic Molding Process & Injection Moulding

The Plastic Mould Processes:

Injection Moulding

In Injection Moulding, melted plastic material is forced in to a mold cavity. The moment in time cooled, the mold could possibly be removed. This Plastic Mould method is normally used in mass-production or prototyping of the product. Injection moulding equipments experienced been created from the 1930’s. These could possibly be accustomed to mass create toys, kitchen area utensils, bottle caps, and cellular cell phone stands to recognize a few.

Blow Molding

Blow molding is like injection molding except that warm fluid plastic material pours away from the barrel vertically within of a molten tube. The mold closes on it and forces it outward to conform toward the within circumstance from the mold. When it is cooled, the hollow element is formed. Illustrations of blow molding products are bottles, tubes and containers.

Compression molding

in this sort of Plastic Mould, a slug of hard plastic material is pressed in between two heated mold halves. Compression molding ordinarily utilizes vertical presses instead from the horizontal presses employed for injection and blow molding. The components created are then air-cooled. Costs of equipments employed for compression molding are moderate.

Movement image Insert Molding

This Plastic Mould method imbeds an image under the surface area of the molded part. A substance like movement image or material is inserted in to a mold. Plastic material is then injected.

Fuel help molding

Also acknowledged as fuel injection molding is accustomed to create plastic material components with hollow interiors. Partial shot of plastic material is then implemented by high-pressure fuel to fill the mold cavity with plastic.

Rotational Molding

Hollow molds packed with powdered plastic material are secured to pipe-like spokes that extend from the middle hub. The molds rotate on separate axes at once. The hub swings the complete mold to some closed furnace space making the powder to melt and stick toward the insides from the tools. Since the molds turn slowly, the means proceed in to a cooling room. Here, sprayed consuming water experienced prospects to the plastic material to harden in to a hollow part. On this sort of Plastic Mould, tooling costs are decrease and product costs are high. Cycle time requires about 40-45 minutes.

Structural Foam Molding

Structural foam molding is normally a means of Plastic Mould ordinarily employed for components that phone call for thicker walls than normal injection molding. Inserting only a little amount of nitrogen or substance blow agent to the plastic material substance helps make the walls thicker. Foaming arrives about since the melted plastic material substance enters the mold cavity. A slender plastic material epidermis types and solidifies from the mold wall. This sort of Plastic Mould could possibly be used with any thermoplastic that could possibly be injection molded.

Thermoforming

In this Plastic Mould process, sheets of pre-extruded rigid plastics are horizontally heated and sucked along into hollow one-piece tools. Once the warm plastic material solidifies, its circumstance conforms to that from the mold.

Plastic molding is normally a pretty specialized process. It necessities specialists on this sort of producing business for it to acquire cut-throat from the market. Therefore, a pretty medical and systematic review must acquire earliest made before to steering into this endeavor.

Plastic injection molding manufactruing

Plastic injection molding manufactruing

Plastic injection molding manufactruingis by far the most popular method to manufacture plastic parts in the world today. This process is used for everything from inexpensive commercial products, like disposable eating utensils, toys to severe environment, highly stressed technical components, like critical parts for automotive and aerospace industries. You’ll find extensive use of injection molded parts in electronics world for things like enclosures for cell phones, computers, televisions and the like, as well as in the medical world where things like syringe bodies, breathing apparatus and a wide range of other life-saving devices are employed. No other process has come to dominate modern manufacturing as injection plastic molding, and its use increases every year. Recently, critical steering components for General Motors cars and trucks were changed from stamped and machined steel parts to an injection molded assembly resulting in a lighter part, at lower cost, quieter, and more reliable.  

Injection molding is the process of heating thermoplastic resin to a liquid then shooting it under high pressure into a mold cavity that is the negative image of the desired part, allowing it to freeze, then opening the mold to allow the completed part to be ejected. In most cases features can be built into the mold cavity to give the part everything it will need when finished, so that no other operations are needed once the part comes out of the mold. Textures, or high polishes, markings, screw holes, lens shapes, and any other features needed in the finished part can be built into the mold so the finished part automatically has these features incorporated.  

The beauty of plastic molding is that many parts, even millions, can be made in exactly the same way and will come out the same no matter what. Each piece will have the identical features, dimensions, and physical properties. It is the ideal way to make high volumes because of this consistency. Properly maintained, injection mold tools can last decades making millions of parts per year. Properly set-up and controlled, the 20 millionth part will be identical to the first part in every measurable way. No other manufacturing process has the potential to operate at this consistency.  

Multiple cavities of each part can be built to the plastic molds, so that each time the mold opens, you make 8 or 16 or some other multiple of parts for each cycle of the injection moulding machine to really increase the production rate and greatly decrease the cost of making a part. In some cases several different parts, for instance a right and left hand version of an enclosure can be made in a single tool as well to reduce the number of machine cycles required to make multiple parts of an assembly, increasing production and lowering the cost. Injection moulding also offers flexibility not possible with any of the other manufacturing processes.  

tooling.co is A Chinese injection molding company that offers one of the lowest plastic molds and plastic molding service and scrap rates of any other manufacturing processes as well. Since no second operations are generally required, no material is cut off and thrown away. It is possible to use a special technique to completely eliminate even the small pathways the plastic flows through to cut the material scrap rate to virtually zero, or often, any plastic removed in the process can be reused by pelletizing it and mixing it back into the fresh plastic resin in closely controlled proportions. These capabilities mean a higher percentage of the raw material becomes part of the finished part than in any other process. Injection plastic molding is highly efficient. 

Plastic Molding Machines

Plastic Molding Machines

Over-mold plastic molding and double injection molding are two distinctly different molding methods even though both are used to combine multiple polymers into a single part. Because of this similarity, the two are often confused or misapplied by the design engineer. The more finite capabilities of these two molding methods differ as much as their required tooling, machines and often, the resulting part cost. Choosing the right method can be a critical factor usd in achieving targeted features, cost and time-to-market. Both methods can be used to create the soft-touch products popular in today’s marketplace. However, both methods can be applied to other applications where multiple polymers must be combined into a single part. Over-mold injection molding is used for parts that do not require fine detail and can absorb the higher cost of machine time and labor. 2-shot injection molding is reserved for parts requiring fine detail and low part cost.

The 2-shot injection moulding process creates the first plastic component, and the material molded round it, using a single mold and a 2-shot injection molding machine. 2-shot machines have two-barrels (one for each material) and they have the ability to rotate the mold. The machine injects the first shot material into cavities on one side of the mold, rotates the mold 180 degrees, and then injects the second shot material onto the first shot. The first and second shots occur at the same time. When the mold opens, it ejects the completed parts from the second shot cavities and it rotates the mold to position the first shot for the second shot. This is accomplished in a machine running in an automatic cycle. Because the 2-shot injection molding process is fast and highly repeatable, the shrinkage of the first shot is very consistent and two materials can be molded together with virtually no flash. 2-shot molding is the process of choice when molded-in graphics or other fine details are required. The elimination of the shrinkage variable allows 2-shot molding to produce details impossible to achieve with over-mold injection molding.

Double injection molding

As with any process, there are advantages and disadvantages associated with plastic injection molding. The advantages outweigh the disadvantages for most companies; they include being able to keep up high levels of production, being able to replicate a high tolerance level in the products being produced, and lower costs for labor as the bulk of the work is done by machine. Plastic injection molding also has the added benefit of lower scrap costs because the mold is so precisely made. However, the disadvantages can be a deal breaker for smaller companies that would like to utilize plastic injection molding as a way to produce parts. These disadvantages are, that they equipment needed is expensive, therefore, increasing operating costs. Thankfully, for these smaller companies, there are businesses that specialize in custom plastic injection molding. They will make a mock up mold to the exact specifications, run it through the complete process and present the completed piece along with an estimate to complete the job to the customer.

Thermoplastic injection molding is the most widely used of all plastic processing methods. The injection molding machine reduces pelletized raw material and colorants into a hot liquid. This “melt” is forced into a cooled mold under tremendous pressure. After the material solidifies, the mold is unclamped and a finished part is ejected. Injection molding offers the lowest piece prices available, but tooling prices are generally the highest. Thermoset injection molding is similar to thermoplastic  injection molding except that uncured thermoset resins are mixed, injected, and held in the mold until cured. As with thermoplastic molding, the price per piece can be low, but the tooling prices are generally very high.

Thermoplastic Plastic Moulding

Thermoplastic Plastic Moulding and Plastic Molding Company

Thermoplastic plastic moulding is the most common way to manufacture plastic parts. Thermoplastics are polymers that can be heated to soften or melt, and cooled to solidify as a physical change, rather than a chemical change that takes place during molding of thermoset materials.
In a plastic molding company,The thermoplastic injection molding process begins by adding pelletized material to a hopper. In most cases, the material must is dried prior to molding, and frequently requires the addition of a color concentrate before loading.

The material is gravity fed into a heated barrel and screw. Rotation of the screw results in shearing action on the raw pellets causing them to melt. The screw rotation also pushes the molten plastic forward in the barrel toward the mold. The material is then injected into the closed mold at high pressure through a runner system to fill all the cavities.

The plastic mold is clamped shut under enough force to keep the mold halves together while the molten plastic is flowing. On a cold runner system, the plastic in the runner solidifies and must be discarded or ground into pellets to be reused, which we refer to as “regrind.” If a hot runner system is used, the plastic in the runner stays molten, and no material is wasted. When the mold cavities are filled, the part cools until rigid enough to be ejected. Part cooling within the mold is accomplished through water lines cut into the mold. At the completion of the cooling cycle, the mold opens and the part(s) are ejected for part removal.

Process called “decoupling” can be used for thermoplastic injection molding. In this process, the cavities are filled to approximately 95 percent of their capacity using high injection pressures. At a specific programmed position of the injection screw, the pressure is reduced and the 5 percent remaining portion of the mold cavity is filled at a lower pressure. This process eliminates over packing of the molded part and the resulting high internal stresses caused by over packing.

Plastic Mold Company Management

Job Shop Management Software Can Really Help A Plastic Mold Company

Wouldn’t it be great if the was some kind of job shop management software that actually helped run your business? One that was designed for small to medium sized companies in a real-world job shop environment?

Personally, I think Plastic injection mold making and plastic injection molding must be two of the most difficult to mangage businesses anywhere. But, maybe other industries say the same thing!


You have deadlines, due dates to meet

There is so much to manage and so little time to manage it

  • Plastic Mold Company to keep track of: steel, graphite, copper, mold bases, components, special items, cutters, grinding wheels, WEDM wire, etc.
  • Quotes need to be made and tracked
  • Progress reports must be made
  • Design must be done and kept current
  • Labor costs need to be tracked
  • Labor divisions need to be analysed for future quoting
  • And on and on and on

No modern business can function very long without serious shop management. A quality job shop management software program could make life a lot easier, if it really worked as advertised. The days of “winging it” are long gone. You might get away with it here and there, but in today’s competetive environment, you need more precise control over your operation.

Looking for good plastic mold company then china plastic injection mold could be one of the most important information for your new products development,

What about JobBOSS software?

JobBOSS, from Exact Software, is a real world job shop management software maker that actually has a program made specifically for mold and tool-and-die builders. It isn’t everyday that anybody even knows about moldmakers! What sets them apart is their experience and fully integrated program.

  • Made for small to medium sized job shops whose orders are custom
  • Made for the real world where customers demands are high and always changing
  • Enables you to know the profitability of each and every job, even as it is constantly being updated
  • It is easy to use and requires no extensive set-up time. You can use it on your next job
  • Has integrated purchasing that is tied to the job

Life in a plastic injection mold making job shop, or even a captive shop, is feast or famine, and when it rains it pours! Once you get your operation set-up in this software, you can experience the relative security of knowing what is really going on. This can really help with the stress levels and shop atmosphere as well. I know, I have personally seen it in action and it really works.

You can find out more about JobBOSS here. Just fill out the form and check your email inbox for all the information you need!

EDM Tooling

Which EDM Tooling Sytem Is Best?

There are several very well designed and reliable EDM tooling and electrode managing systems on the market today. Each has it’s advantages over the other, but all are quite good. Time spent analyzing the various systems available is time well-spent. Your needs are unique, and you will be “married” to the one you choose for a long time.

There is no question at all regarding the benefits of using an EDM tooling system. Your quality will increase, your productivity will increase and your plastic injection mould makers will quickly see the benefits. The electrical discharge machining operators will also be very grateful that they no longer need to indicate and locate everything ‘to death’.

Time is money, and an EDM tooling system saves a lot of time.

You might need to change your shop culture


A common problem with implementing a new electrode holding system is the change in shop culture that is required. This was especially a problem in the past. One of the best ways to do this is to designate two moldmakers as the team to study and develop the idea. They will feel personally responsible and take ownership of the project, which will influence the rest of the shop.

You must make sure your moldmakers understand what you are doing and why. Change is always difficult and many moldmakers have been doing things a certain way for many years. They often see this new system as a waste of money and unnecessary.

Time spent discussing the change, and showing how and why things will improve will go a long way. Very soon, everyone will easily see the rationale behind the decision and be “on-board.” A demonstration of the repeatability is a great way to convince the skeptics.

Once your moldmakers can see the labor savings and ease of use, they will be enthusiastic. Very few people really like making electrodes the “old school” way. For one thing, it is very tedious and messy. read more about EDM tooling please go to our plastic mold manufacturing company.

Features to look for in EDM tooling



  • Repeatability. In real life can it repeat within the tolerances claimed by the manufacturer?
  • Ease of set up and use. Does it take a lot of time and labor to mount electrodes and set it up in the EDM and CNC machining center?
  • Is it cost effective? Take some time to analyze the cost savings as well as the “headache” savings. Any EDM tool holding system is expensive, but, over time, the savings can be dramatic.
  • Does the system have compatible fixtures for various sizes of electrodes? You should be able to use different size holders interchangeably.


    Not everyone uses EDM tooling!

    Sure, there will always be the odd time when you need to use a “stick” electrode, maybe even often on certain applications. But any serious mold making shop today is crazy to still be using angle blocks, vee-blocks and so on. It is so incredibly inefficient to make tedious set-ups by hand, over and over again.

    Yet, this is precisely the case in the newly emerging areas, such as China. It is quite common to get a box of stick electrodes with the plastic mold that they have just sent. They figure that their labor is so cheap that they can afford to operate this way.  Most likely, it is just a matter of time before they figure out that this is a foolish way to operate. It just makes sense to have an integrated system that is reliable and that eliminates the need to constantly be checking for alignment and location.

Injection Molding Process

The injection molding process

In the injection molding process, thermoplastic resins are melted and the melt is forced (injected) into a mold.

     In the injection molding process, thermoplastic resins are melted and the melt is forced (injected) into a mold. After this melt cools until the polymer solidifies, the parts are removed (ejected) from the mold. Injection molding permits mass production net shape manufacturing of high precision, three-dimensional of plastic parts[1]. One of the most common plastics manufacturing processes, injection molding can produce parts weighing as little as fraction of a gram or as much as 150 kg[2]. The process currently consumes 30% of polymeric resins[3] of which 90% are thermoplastics (i.e., capable of being remelted)1. Major advantages include capabilities to produce parts with: 1) virtually unlimited complexity, 2) fine details and good surface appearance, 3) controlled wall thickness and excellent dimensional stability, and 4) requiring limited or no finishing.

The five important thing in the injection molding process are the

1. Injection molding machine

2. Mold

3. Material

4 Method

5. Man (i.e., operator).

While there are many variations of each M, this discussion is limited to single-stage reciprocating screw injection machines and the flow of thermoplastic polymer melts in two-plate cold runner molds.

1. Injection Molding Machines

As illustrated in Figure 1, injection molding machines have three major components: the 1) injection unit, 2) clamping unit, and 3) controls. The injection unit plasticates (melts) and injects the polymeric material into the mold. The clamping unit supports to the mold and provides the mechanisms for opening and closing of the mold and for ejection of molded parts.Injection Mold China

Figure 1. Injection molding machine

During a thermoplastic molding cycle, the clamp of the injection molding machine closes, thereby closing the mold. Molten plastic located between the nozzle and screw in the barrel of the injection unit is forced (by the screw) into the mold. The controlled volume of melt injected into the mold typically fills the cavities to about 95 to 98% of their total volume. After injection is completed, the screw is pressured for a given period of time. In this packing stage, more melt is forced into the mold to compensate for shrinkage of the melt as it cools. The packing stage is followed by a holding stage, in which a controlled pressure is exerted on the screw for a specific length of time. Holding pressure prevents the melt from flowing back into the runners. When the gate freezes (solidifies), melt can no longer exit the cavity and the holding stage ends. While the melt cools immediately upon entering the cavity, a ¡°formal¡± cooling stage follows the holding stage. During this period, the part cools until it is capable of withstanding ejection forces. The screw also rotates to melt more plastic and build up the molten plastic shot for the next molding cycle. At the end of the cooling stage, the mold is opened and the part is ejected.

Today lots of person or companies are looking for Injection Mold China partners for their plastic molding business, this is high speed to American and Europe

The times associated with a convention,

all molding cycle are shown in Figure 2. For 2 to 3-mm thick parts, filling occurs in less than 5 s, packing requires one-third of the fill time[5], the holding time depends on the gate size, and cooling is longest part of the cycle. Thin-walled parts (i.e., wall thickness is less than 1 mm), however, filling in less than 1 s, typically have no packing or holding stage, and cool rapidly. go to our plastic molding official website to get free quote for your plastic molding project.