Custom Plastic Injection Molding Services:
Inno Molding is a one of the leading plastic injection molding companies in Shenzhen China, we provide high quality, flexible, low cost of plastic injection molding services to worldwide clients in application of automotive, medical, consumer electronics, home appliance, and other commercial products.
Our injection molding shop is well-equipped with 18 sets of automatic injection molding machines, ranging from 50T~450T, and available for part weight from 0.5g~ 3.0KG. The plastic resin includes PC, ABS, PMMA, PP, POM, PA6, PA66, PE, PBT, PS, PSU, TPU, TPE, TPR, silicone...All of injection molded parts we produced would be 100% inspected with dimensional, visual, and functional before shipping. So that our clients will get high quality products from us.
What Makes our Injection Molding Service Better?
1. Golden Sample to Avoid Mistakes
Before injection molding production, we always request a golden sample that signed by client. As the golden sample is comprehensively evaluated by means of dimension checking, fitting test, and appearance review. In this way, we can quickly and physically check our product quality.
Our on site QC will strictly check and compare our injection molded parts. If any deviation found, we will pause our injection molding production immediately until the problem is solved.
2. We Use Experienced Workers
An experienced worker is one of the most important factory to produce high quality injection molded products, because the experienced worker is not only familiar with machine operation, but also has a great mind on product quality control.
At Inno molding, we hired all of workers who have at least 5~8 years of experience in plastic injection molding, as the worker is our basic quality inspector, who produce and monitor the whole injection molding process.
On opposite, unlike other plastic injection molding companies, who might want to save salary and use new workers without out background or experience on plastic injection molding, which lead to some serous quality issue to happen.
3. Product Training Before Production
If any new project to launch, our engineering team will hold on a product meeting to train all of our workers, QC, and technicians. Ensuring they are all aware of our manufacturing requirements on product quality and lead-time. A written work instruction will be set aside of injection machine table.
4. High Quality Mold tool
A high quality injection molded product comes from a quality mold tool, prior to injection molding, we emphasize our technology and energy to make as higher quality mold tool as possible. We improve mold quality from design, steel quality, machining process, and fitting handwork. All of mold tool must be tested and trail-run for at least 200~1,000 pcs. When it run smoothly and steadily, we move the mold tool to injection molding production.
5. Top Level of Plastic Rein
Unlike other injection molding factories, In order to purse more profit, they might use recycled plastic material. At Inno molding, we never use worse quality plastic resin. All of our material are directly from first hand resin supplier.
We use top level quality plastic resin from global famous resin manufacturers, like Chimei from Taiwan, LG from Korea,GE & Du Pont from US, Bayer from Germany, Tecnica from Italy, EMS from Switzerland, etc.
6. Brand New Injection Molding Machine
Being a professional injection molding company, we facilitate our shop with brand new injection machines that imported from Japan and Germany. It enables us to produce precision and excellent injection molded products.
We perform a monthly and quarterly machine maintenance plan by cleaning, lubricating, and calibrating. Any of our machine can traced for maintenance recorders.
Our Quality Control:
We are an ISO9001-2008 & ISO14001-2004 certified injection molding company. Each of our project starts with professional team including project managers, project engineers, production manager, QC manager, QC inspector, and shipping manager.
We perform strict quality plan from raw material to finished products. Before shipping, all of injection molded products will be checked and monitored by dimensional measurement, cosmetic inspection, and assembly testing. Finally we document those data and make enclosure along with shipment to customer for review.
FA Insepction Report(First Article Qualification)
SPC Report(Statistical Process Control)
DFM Evaluation(Design for Manufacturing)
FMEA Analysis(Failure Modes and Effects Analysis)
Full dimension inspection for all of mold components.
1. Product Design Assistance
Perhaps we are not a professional product design company, however our engineers have rich experience on mechanical structure design(particularly in plastic structure design), which enables us to provide product design assistance to those clients who might not be so familiar with plastic part design. Because most of time, a product designer have less knowledge on mould tool and plastic injection molding process, which could lead to an incorrect plastic part design that could not be available for injection molding production.
2. Material Choosing
Choosing a right plastic material is a little challenge for some of product designer, as we need a deep understanding of material property, cost, and injection molding property. Our engineers have over 10 years of experience on working with plastic product, who knows all of practical criteria for plastic resin and injection mold tooling. We can help clients to choose economical, practical, and efficient plastic material after consideration of product function, structure, using condition, etc.
3. Part DFM Evaluation
Whatever how perfect your design might be, but there is always a necessary to perform a part DFM before injection molding design. Our sophisticated engineers had years of work experience in product design and injection mold design, we could combine our consideration for both product structure and mold tool design.
Most of time, we will have to help clients improve draft angle, thickness of wall, ribs, and radius on plastic part. And try to avoid sharp steel on mold tooling, which could shorten the life-time of mold tooling. On the other hand, we will also help to check part fitting, tolerance, and appearance.
Before moving a project to injection molding stage, it’s necessary to make prototype to verify if their design exists any fault or imperfection. If needed, we can also help clients to do this job.
We utilize 3D printing, CNC machining, SLA, or SLS to make physical prototype to validate product production, fitting, structure. So that we will be able to improve and refine tolerance, material, and dimension. By using a prototype, we can clearly anticipate injection molding cost, efficiency, and quality issue.
How to Work a Plastic Injection Molding Project With us?
Step 1. Send an Inquiry
Should you have any injection molding request or question, you are welcome to contact our sales staff or engineering team for a free project consultation.(we will respond you within 24 hours).
If you want to obtain a RFQ from us, you would please send us the information as below:
1). 3D drawing in stp format (or igs format), and 2D drawing(if have)
2). Part Material, Part Color
3). Your Order Quantity
4). Other specification(like printing, assembly, etc)
Step 2. Order Confirmation
Once you got an quotation from us, you are encouraged to respond us as soon as you can. If our offer is acceptable, please contact us for an order confirmation.
To finalized your order, clients need to make an 50% of deposit for mold tool cost to start our cooperation. The rest of 50% of payment would be made after the final sample is confirmed by client.
Step 3. Mold Tool Making
After an order is confirmed, we will start to design and make the mold tool that will be used for injection molding production. During this stage, our mold designer and engineering staff will work closely with clients to perform product DFM, product design refining, mold DFM, as well as mold design. We will help clients to optimize their product design and provide the most cost-effective and durable injection mold design solution.
A simple mold tool takes about 15~20 days to finish, a medium complexity mould takes about 20~25 days, and highly complex mold will take longer time(it really depends on mold complexity)
Step 4. Mould Trial and Sample Submission
Once the mold tool is ready for trail, our mould maker will arrange a mold trail to test the mould tooling. Our on-site QC and project engineer will follow up the whole trail process. And ensure we will have right part material, part color, and fulfilled injection molded products. A mold trail report and sample inspection report will be prepared after mold tool. We will comprehensively evaluate part dimension, appearance, and fitting with whole product.
A 10~20 samples will be submitted to client for review, and we will gather customer’s feedback and our own inspection result to improve products. And get everything ready for mass injection molding production.
Step 5. Pilot Run
At Inno molding, we verify our mold tooling and quality with step-by-step process. Whatever our client is an expert at plastic injection molding field, or he know nothing about injection moulding production, we always recommend a 200~1000 pcs of pilot run. In this way, we can greatly identify any quality issue or design imperfection. And it’s easier to improve defects if we found. Otherwise it could be time and money waste to start mass production in case any problem arise.
Step 6. Mass Injection Molding Production
After everything is confirmed, it’s time to move our project to mass production. We take systematic production management measure to control our quality from raw material to finished products. Prior to production, our injection molding supervisor will release related work instruction and golden samples aside of injection machine. And our on site QC will inspect product quality every 15 minutes
Step 7. Shipping
We provide global logistic service for our clients. Normally for sample and small volume of products, we ship goods to clients by air(DHL, UPS, TNT, Fedx,etc), which takes about 3~5 days to arrive any destination globally. However, for some large order or mold tool, we will suggest customers to use economical shipping process(like ocean shipping, or TNT economical service). But it will take longer time to arrive as it’s much cheaper.
What is Plastic Injection Molding ?
Plastic Injection Molding is the most common manufacturing process to produce plastic parts for nearly every products.
The injection molding process needs to use injection machine, plastic resin, and injection mold tooling. It requires a ram or screw-type plunger to force molten plastic material into a mould tool where the molten material cools and solidifies to obtain the desired plastic parts or products.
Since injection molding has good repeatability, productivity, and stability, it is widely used in many different industries to manufacture large-scale of products. Like automotive, medical, household, electronics, etc. Needless to say, you can image how important the plastic injection molding technology is!
Advantages of Plastic Injection Molding:
Complex Part structure available
Compared to other manufacturing process, plastic injection molding has big advantage on complex part geometry, it means you can design a plastic part as complex possible to realize product function while not increasing too much cost. This is what any other molding process or machining process can never achieve it.
High Efficiency, Easy Mass Production
As we know, there is a mold tool on injection machining while injection molding process. It takes seconds or a minute to get a plastic parts. The manufacturing cycle is quite short compared to CNC machining, die casting, or other molding process. Therefore it’s easy when you are going to produce it in large volume.
Flexible Color and Material
When a plastic injection molding production, it is very flexible to allow customer to have different product color and different material manufactured. it will quickly obtain different style of molded products.
Easy for Engineering Modification
As we know, any of product development might change a lot so as to optimize a better products. If you design a plastic parts, you can make engineering change easily and conveniently by mold modification or injection molding parameter adjustment.
Up to now, plastic injection molding is the most cost-effective way to obtain products. Because the cost of resin and manufacturing process is much lower than metal machining or other molding process. (about 5~10 times cheaper). This is why most of product components are consisted of plastic parts.
Six Typical Injection Molding Process
Step 1. Mold Installation
When a mold trial or an injection molding production, we need to locate the plastic injection mold from mold tooling shop (warehouse) onto a plastic injection machine. Since the mold tool is so heavy, we have to use a crane to move and lift it. By four big screws to fasten the mold on injection machine tightly, it is very important process, because the fastening force will directly affect the clamping force.
Step 2. Material Baking
As you know, the injection molding process is that the molten plastic material flows into the mold tool. To perform this process, we must pre-bake the material to reach a certain of temperature. If we don’t do this process, the molded parts might come with defects or not full filled.
Step 3. Mold Clamping
When it’s time to start injection molding process, we should keep the two half mold(cavity side and core side) closed tightly on injection machine. If we don’t clamp the mold with proper force, there will result in a flash defect for injected parts. However different size of mold requires different clamping force. Normally, the bigger mold would need larger tonnage of injection machine.
Step 4. Material Injection
Injection is also called material filling. The plastic material is forced to fill into a mold cavity quickly by a high pressure device( the barrel of screw). It’s one of the most important factor that affect the quality of final molded parts. A short injection might result in unfulfilled parts or over injected parts( overflow or flash). However the injection volume is controllable by injection power, filling volume, injection time, and injection pressure
Step 5. Parts Cooling and Solidifying
After injection process, the molten plastic material with high temperature stays inside of mold cavity. Since every mold is designed with cooling system( water or oil), which helps the filled plastic to cool down and solidify. And finally it will form an desired part. When there is uneven thickness of wall, there is likely to exist some shrinkage defect on the parts. Of course, the shrinkage issue could have many potential reasons. But cooling system is one of the most important factor for parts shrinkage.
Step 6. Ejection Out
It’s time to take out the injection parts from a mold tool, but we have a special device for this process(ejection pin or ejection plate). The injection machine will collaborate with mold tool to push out the parts and fall down from mold tool. Up to now, we can say the whole injection molding process is finished.
The 5 Key Factors in Injection Molding Process
Injection molding is a complex process. The quality of injection molding parts could be affected by many different aspects, which can mainly summarized as five typical factors that are pressure, speed, position, temperature, and time. We would like to introduce them briefly as below:
The injection pressure is originally given by the hydraulic system of injection machine. During the injection molding process, this injection pressure is passed by the screw and nozzle of injection machine until mold cavity finally. It could affect the product appearance(like shrinkage, injection mark, air mark) and dimension a lot if we use different injection pressure(higher or lower).
Normally we use high pressure for big size, complex part structure, and thin wall of part. On opposite, for a thick wall of part, we will have to use low pressure.
It means the holding time during which the melted material is filled into mold tool cavity under a certain pressure while injection molding process. The function of holding pressure is to maintain a pressure to compensate for resin shrinkage when it cools and solidifies, Therefore keeping enough holding pressure and holding time will significantly influence the injection molded parts quality.
When a injection process finished, the injection screw would have to retract, in this time, there must arise a pressure(we call it back pressure). In theory, back pressure should never exceed 20% of the injection molding machine pressure. Most of time, we try to use as lower back pressure as possible.
In order to withstand the injection pressure, there must apply for a certain clamping pressure during injection molding process. The clamping pressure provided by a mechanical clamping device that facilitate on injection machine, which is adjustable for high, middle, or low pressure.
We need to choose appropriate clamping pressure according to different mold size, injection type, size, and injection plastic resin. If a mold clamping pressure is too low, there will result in flash or unfulfilled parts. On opposite, if a over-clamped pressure, it could damage a mold tool.
Even though there is no fixed rule to define an exact speed for every part. Since there are lots of different plastic resin, injection machines, and part structure. however, relatively to say, a thin wall of part requires to use high speed injection process, but a thick wall of part, we will have to use lower speed. So an experienced technician is necessary when we define an injection molding parameter.
Per our experience, we use 0.1-10 for buffer flow, 11-30 for slow speed, 31-60 for middle speed, and 61-99 for high speed.
Injection speed refers to the time of molten resin accumulation from nozzle to mold cavity, we need set up injection speed according to appropriate part material and structure.
Normally we use a lower injection speed for those resin with good flowability, like PP, LDPE, TUPE, TPR, TPU, PVC, etc. and for resin with medium flowability with middle thickness of wall(1.5mm or above),we will use medium injection speed (like ABS, HIPS, GPPS, POM, PC+ABS, HDPE). However for material with worse flowability(PC, PC+GF, PA+GF,PBT+GF,LCP), we will have to use high speed injection process.
Material Molten Speed
A proper material molten control is as important as other injection parameter. We can’t ignore it when injection molding process. Material molten speed must follow up the injection cycle.
A quick molten resin will result in over-burned material that could change part color a lot, but a slow molten speed would lead to prematurely molten part, which looks like small injection dot.
Mold Open Speed
Because there are lots of different mold structure, we should adjust appropriate mold open speed to adapt the best injection molding process. For instance, a multi-plates mold(three plates mold or more), a complex hydraulic cylinder sliders, and screwing sliders molds should be opened slower. But for some simple structure mold without slider can be exerted quicker.
It depends on mold structure and part structure to determine how quickly we should set up the ejection system. In theory, we should leave the ejection speed as slower as possible as long as the plastic parts is not damaged or deformed when ejection process. In this way, we can save the life time of ejection system
When setting up an injection molding parameter, we need to set a right injection position based on part weight and structure. Ensuring our part is fully-filled. Yet it doesn’t come with flash or other defects.
Mold Open Position
Mold open position is mainly depends on mold structure. If an incorrect mold open position will damage either injection molding machine or mold tool.
Ejection Pin Position
In theory, the length of ejection out is two times of mold core height. However most of time, we did not follow this rule. Per our experience, the height of ejection could be adjusted as soon as the parts is ejected out while not damaging plastic part.
The Barrel Temperature of Injection Machine
The barrel temperature will directly or indirectly affect resin flowability, color, shrinkage, deformation, etc.
Different resin has requires different injection temperature, however we have a basic temperature data for common plastic material.
Here below is a barrel temperature list:
High Impact ABS: 230°C~260°C
Low Impact ABS: 190°C~230°C
High Density PVC: 160-200、
Low Density PVC140°C~180°C
High Density PE:240°C~300°C
Low Density PE: 180°C~230°C
High Density TPE: 170°C~200°C
Low Density TPE: 140°C~180°C
High Density TPU: 160°C~200°C
Low Density TPU: 120°C~160°C
The mold temperature setting is mainly based on resin flowability. For example, PC and PA+GF have a relatively worse flowability, we need to use a high speed injection with high mold temperature. However for clear PC part, we just need a lower mold temperature for injection molding.
Here blow is a reference mold temperature list for different resins:
ABS=30°C~50°C（Part is easy to deform or has high appearance requirement: 60°C~110°C）
PC=50°C~80°C( Thin part or part has high appearance requirement: 80°C~140°C)
HIPS=30°C~50°C( Clear PS or part has high appearance requirement: 60°C~80°C)
PMMA=60°C~80°C( Thin part or part has high appearance requirement: 80°C~120°C)
PE= 10°C ~50°C
TPE, TPR, TPU=10°C ~50°C
PA, PBT=30°C ~60°C（If they are combined with GF: 70°C ~100°C）
The environment temperature seems not so important for most of plastic parts. However, if we require a tight dimensional stability, we need a stable temperature workshop. Like medical parts, airplane parts, precision equipment parts, etc. We will need to keep an injection environment temperature about 15°C ~20°C
As long as we meet product requirement, we try to use the shorter injection time. Normally a thin wall of parts requires a shorter time, on opposite, the thicker wall parts need slow injection time. If any special part structure, we may need to adjust injection time gradually until the best quality product is injected.
Holding Pressure Time
In principle, the holding pressure is used to control part shrinkage and maintain dimension stability. The molding pressure time depends on part structure and requirement. Relatively to say, we use longer holding pressure for thick wall of parts. On opposite, we will adjust it as shorter time.
As we know, all of injection molded parts will have a shrinkage issue after it is injected from machine. We need get it cooled down and solidified before they are in use. Normally it takes about 12~24 hours for complete cooling. After this time, the molded parts will keep almost the same shape and dimension.
Because of resin shrinkage matter, an injection molded part would need time to cool and solidify. Normally we can either wait for 3~5 hours or put the part inside cold water before we check the part dimension and appearance. Otherwise your measurement data will be inaccurate or has big deviation from its real data.
Common Defects of Plastic Injection Molding Products:
Flash – The additional material overflew from desired shape or dimension
Shrinkage – The material reduction portion after the plastic product cools from mold tooling. Normally there will be a shrink mark on the surface a plastic product.
Deformation – When the final plastic product come out from injection machine, the product looks not straight obviously or measured by a certain equipment.
Flow marks – An outstanding pattern existing on the surface of plastic product, it normally result by slow injection speed.
Short Shot – The molten plastic does not fully fill in the mold cavity, resulting in a portion where lacks plastic material.
Welding line – It’s also called the juncture line where normally happens on round feature that two flow fronts meet and are unable to join together during the injection molding process.
Burn Marks – It looks like rust colored, that appear on the surface of the injection molded products.