Use of Plastics in Medical Industry

 Medical equipment involves multiple sectors pharmaceuticals, machinery, electronics, plastics, etc. In which the rapid development of China plastic medical devices. Plastics have been used widely to create medical tools. And devices like surgical gloves, syringes, insulin pens, IV tubes, catheters, inflatable splits, etc. Such products are created for one-time use. Help prevent the spread of dangerous diseases by eliminating the need to sterilize and re-use a device.

Medical uses for plastic materials include:

Thin tubes called catheters are used to unblock blood vessels. The deposit obstructing the vessels can be broken down with a tiny spiral-shaped implant called vessel support. The vessel support is made of plastic developed specifically for the medical field and charged with active substances.

Plastic pill casings are made of tartaric acid-based polymers that gradually break down. Slowly releasing the required medication over the required amount of time. These tailor-made pharmaceutical delivery systems help limit the number of pills a patient must take to get the required dose.

Synthetic materials can also play an important role in repairing diseased arteries that cannot be helped via vessel support. After removing the affected section of the aorta. A flexible plastic prosthesis bridges the gap.

People with severely impaired hearing can now have plastic implants inserted that allow them to hear the sound again. The implant is made up of several components including a microphone. A transmission device that is connected to a micro-computer worn on the body. Additionally, there is a stimulator and an electrode carrier with 16 electrodes, and 16 different frequency ranges. This device transforms acoustic impulses into electrical ones bypassing the damaged cells and stimulating the auditory nerve directly.

There is also a whole array of plastic disposable medical products. Including bedpans, insulin pens, IV tubes, tube fittings, plastic cups and pitchers, eye patches, surgical and examination gloves, inflatable splints, inhalation masks, tubing for dialysis, disposable gowns, wipes and droppers, urine continence, and ostomy products. The use of plastic materials in hospitals is almost endless.

[caption id="attachment_3881" align="alignnone" width="605"] Use of Plastics in Medical Industry[/caption]

The Advantages of Injection Molding Techniques in Medical Applications:

(1) A polymer material with good mechanical properties, and chemical stability. More suitable for medical use.

(2) A rich source of polymer materials. Inexpensive disposable medical supplies are made to avoid traditional material products due to high prices.

They had to repeatedly use disinfection and problems caused by secondary infections.

(3) More easily modified plastics have good tissue compatibility. Flood compatibility of products.

(4) Made of plastic low cost, suitable for a variety of molding methods. Ease of processing into complex shapes. And the development of new medical products.

Medical Grade Plastics

The standards and limitations for the use of materials for medical applications are very stringent. The invention of various types of materials. With suitable properties and injection molding techniques. The possibilities of the use of plastic resins for medical applications have increased.

The following are the key considerations for selecting medical-grade plastic resins.

1. Strength: Depending on the type of medical equipment being considered.
2. FDA rules Are different for different medical devices (tubings, implants, surgical instruments, etc).
3. Thermal and Chemical resistance: Important aspects, considering medical sterilization needs.
4. Molding techniques: Different plastic resins can be selected depending on the molding technique being used- injection molding or insert molding.
5. Operating conditions: Includes factors like corrosion resistance, temperature, strength, flexibility, radiation exposure, etc present while the device is used.

Compared with ordinary plastics, medical plastics molding parts require higher:

(1) Since most toxic monomers and oligomers. Medical plastics are strictly limited to the residual of the foregoing.

(2) Plastic molding in the polymerization process inevitably comes into contact with the reactor, and metal catalysts. Which often contain trace metal ions, according to the medical plastics GB. The requirement for zinc, lead, cadmium, copper, barium, and tin. Other metal ions residual cases are clearly defined.

(3) Requirements for medical plastics molding with high purity. Narrow molecular weight distribution.

(4) Chinese plastic molding processing or modified in the process need to add various additives. Such as the amount of plasticizer in PVC medical products is often as high as 30-60%. This required maximizing the use of toxic chemicals. To prevent long-term use or reduce the precipitation of additives to affect product performance and treatment.

(5) In accordance with the requirements of medical plastic. We often need to make products with surface hydrophilicity. Anti-radiation sterilization, and other functions.

 

Medical supplies

 

How is CNMOULDING Supporting Medical Device Manufacturing?

CNMOULDING is currently supporting the medical industry through rapid prototyping, mold creation, and engineering design. The medical industry is quickly advancing technology and products that are being developed specifically with plastic injection molding in mind. CNMOULDING has a rigorous quality initiative for day-to-day operations, which was recognized during our ISO 9001: 2015 certification. Our management system keeps our molded products at the highest quality before distribution to a finished device manufacturer or an end consumer.

Why Does CNMOULDING Recommend Plastics for the Medical Industry?

Reduced Manufacturing Side Effects – Plastic injection molding produces few side effects and has very little scrap material after the injection molding process.

Reduced Tooling Investment – Metal casting and stamping dies can take 12-16 weeks to complete after the initial design is complete. Plastic injection molding dies can be ready to make products in as little time as 6 weeks. Plastic injection molds can last up to six times as long as casting and stamping die.

Unlimited Design Options – Complex metal product designs often require a significant amount of development time and cost to ensure casting or stamping molds will survive a long life cycle. Plastic injection molding can fill molds faster with better results, and plastic products have also seen a rise from 3D printing as new equipment, software, and materials are in constant evolution.

Corrosion Resistance – Plastic is naturally corrosion-resistant by nature, whereas most metals need a secondary or tertiary operation to apply a coating to resist corrosion.

Reduced Product Weight – Engineered plastics can reduce the overall weight of most products. Reducing weight can positively reduce shipping costs and make ergonomic improvements within a manufacturing process.

Biocompatibility – Medical grade plastics are biocompatible which makes them easier to incorporate into new ideas and redesigns of older products.

Recyclable – Medical grade plastics can be recycled without concern of extra protective coatings contaminating new materials.

Mold making project for thermoplastic elastomer molded parts 

Recently, we produced three molds for Austrian companies, injection molding products are
thermoplastic elastomers. We call TPE. The customer is a medical company, and the product requirements more stringent. We encountered some problems in the production process, but in the end, they are the perfect solution. 

1， Products design

2, Mold design

3. Mold making

mold make

4, Mold making for medical-mold teat

mold teat

5， Work with customers to improve the design

6， The product is covered with a layer of rubber

7， Laser and Silk printing

8， The final product

mold making project for medical

Air Poppet in injection mold

 

CNmoulding Air Poppet in injection mold

Air Poppet in injection mold

Air Poppet in injection mold

 

The popular design of injection mold is generally using the thimble to push out the mold of the product. For the products with high product appearance requirements, most of them do not adopt this way. Because of the reason of the product structure. The top block cannot be used for all products. For example, for a barrel, a product with a special structure of inverted buckling. The surface of the product is an external surface without perforation.

If a general thimble is used to push out the product, it is easy for the product to be sucked. Resulting in the product being pushed out of a depression, or perforation occurs. Affect the appearance and use of the product. At this point, an air poppet is needed. The air poppet is completed to solve the shortcomings of the prior art. The purpose is to provide a product with a simple structure, convenient operation, suitable for this special structure of the barrel and basin, and improve the qualified rate of the product. Reduce production costs and make it easier for products to be completely ejected.

Air pop valves are available in inch and metric sizes. They are designed to break the vacuum created when forming thin-walled or deep-drawn parts such as flowerpot trays and containers. Multiple air cone valves can be used for large or heavy-duty sliders.

Extensive experience serving a wide range of air poppet valve

Taking the new injection mold made by American customers as an example, the round cover product with inner thread is designed with an inverted structure on the core. To prevent the product from sticking to the front core. Ordinary ejectors can no longer meet the required technical requirements, so we replace them with an air pop valve. The injection mold requirement quality is high in the United States because the process standard is not reached during the install air poppet, which leads to the mold test failure.

What is the purpose of the air poppet valve in plastic injection molds? An air poppet valve used to assist injection of molding parts. A small amount of gas is blown into the injection mold cavity (or from the core) at the desired position to assist in separating the moulding portion from the desired mold parting line feature. Examples of using dimethyl, ether air Poppet valve are with deep drawing parts (i.e. drums) or thin-walled molded parts. The timing of airflow is consistent with the injection cycle, which opens the valve to break the vacuum and facilitate partial injection.

Last poppet valve technology

In general, the minimum diameter of the air poppet can be 5 mm, the maximum diameter can be 30 mm, the maximum height of the air poppet can be 50 mm, and the air poppet valve is generally composed of four parts: the shell, the top rod, the spring, and the elastic cylinder pin. There is a more common air poppet valve used in domestic, DME valve also known as VA air valve is used in export mould, CUMSA air poppet valve is the second, and HASCO brand name is relatively less. If the international standard air poppet valve is used, the price is still very high up to now. It usually costs several hundred RMB. The mould of these international standards can basically be produced at home, and the quality is relatively reliable and stable. This kind of technology has been mastered.

Why precision injection molding is difficult?

 

Why precision injection molding is difficult?

 

Precision injection molding is challenging due to several factors that require meticulous control and optimization. Here are the key reasons:

1. Tight Tolerances

Precision molding demands extremely tight dimensional tolerances, often in the micrometer range. Achieving this requires precise control over every aspect of the process, including material behavior, mold design, and machine operation.

 2. Material Variability

Plastic materials can exhibit variations in properties such as shrinkage, viscosity, and thermal stability. Even small inconsistencies in material composition or moisture content can affect the final product's dimensions and quality.

3. Mold Design and Manufacturing

The mold must be designed and machined with high precision to ensure accurate part dimensions. Any imperfections in the mold, such as uneven cooling channels or misaligned components, can lead to defects in the molded parts.

4. Process Control

Precision molding requires precise control over process parameters such as temperature, pressure, injection speed, and cooling time. Even minor deviations can result in defects like warping, sink marks, or incomplete filling.

5. Thermal Management

- Controlling the temperature of the mold and the molten plastic is critical. Uneven cooling can cause warping or residual stresses, while excessive heat can degrade the material or cause flash.

6. Part Complexity

Complex geometries with thin walls, intricate features, or tight corners are harder to mold precisely. Ensuring uniform material flow and cooling in such parts is challenging.

7. Tooling Wear and Maintenance

Over time, molds can wear out, leading to dimensional inaccuracies. Regular maintenance and monitoring are required to ensure consistent quality.

8. Environmental Factors

Variations in ambient temperature and humidity can affect the molding process and material behavior, making it harder to maintain consistency.

9. Material Shrinkage

Different materials shrink at different rates as they cool. Predicting and compensating for shrinkage accurately is essential but difficult, especially for high-precision parts.

10. Quality Assurance

Ensuring consistent quality across large production runs requires rigorous inspection and testing, which can be time-consuming and costly.

Solutions to Overcome Challenges:

Advanced Mold Design: Use high-precision machining and simulation tools to optimize mold design.
Process Monitoring: Implement real-time monitoring and feedback systems to control process parameters.
Material Selection: Choose materials with consistent properties and low shrinkage rates.
Automation: Use automated systems to reduce human error and improve consistency.
Regular Maintenance: Maintain molds and equipment to prevent wear-related issues.

By addressing these challenges through careful planning, advanced technology, and rigorous quality control, precision injection molding can be successfully achieved.

Transparent plastic injection molding defects and solutions

Transparent plastic injection molding is a widely used manufacturing process in various industries.  However, like any other manufacturing process, it is not immune to defects.  In this blog post, we will discuss some common defects that may occur during transparent plastic injection molding and their solutions.

1.  Flow marks

Flow marks are the visible lines or streaks on the surface of the molded part.  They occur when the plastic material does not flow evenly into the mold cavity.  To avoid this defect, it is recommended to use a higher injection speed and pressure to ensure that the plastic material fills the mold cavity uniformly.

2.  Weld lines

Weld lines are the visible lines that appear on the surface of the molded part where two flow fronts meet.  This defect occurs when the plastic material cools and solidifies at different rates.  The best solution is to use a higher mold temperature and increase the injection speed to ensure that the plastic material flows evenly into the mold cavity.

3.  Sink marks

Sink marks are depressions or dents on the surface of the molded part.  This defect occurs when the plastic material shrinks as it cools and solidifies.  To avoid this defect, it is recommended to use a lower injection speed and pressure to ensure that the plastic material does not overpack the mold cavity.

4.  Air traps

Air traps are air pockets or bubbles trapped inside the molded part.  This defect occurs when air is trapped inside the mold cavity during the injection molding process.  To avoid this defect, it is recommended to use a higher injection speed and pressure to ensure that the plastic material fills the mold cavity completely.

5.  Scratches and blemishes

Scratches and blemishes are visible marks or imperfections on the surface of the molded part.  This defect occurs when foreign particles or debris are present in the mold cavity during the injection molding process.  To avoid this defect, it is recommended to use a clean mold cavity and filter the plastic material before injecting it into the mold cavity.

In conclusion, transparent plastic injection molding defects can be avoided by following some simple guidelines.  These guidelines include using a higher injection speed and pressure, increasing the mold temperature, using a lower injection speed and pressure, ensuring that the plastic material fills the mold cavity completely, and using a clean mold cavity and filtered plastic material.  By following these guidelines, manufacturers can produce high-quality molded parts without any defects.

Transparent plastic injection molding

Beauty instrument injection molding

 [caption id="attachment_2266" align="alignnone" width="416"] Beauty instrument injection molding[/caption]

The beauty instrument shell mold injection molding processing, is a subtle and complex production process, want to do it perfectly, in addition to a higher degree of accuracy of production equipment, must also have rich experience in teacher to control, so the purchaser before selecting mould injection molding factory must have a full understanding.

Beauty instrument  injection molding processing

Because the general size of the beauty instrument shell is relatively large, so the need for a larger tonnage of injection molding machine to be competent, but also have to be a two-color injection molding machine. Beauty instrument shell mold injection is a fine technology, it is the appearance of the product, color, product size, product built-in fixed parts, screw holes, etc., have a very high tolerance requirements. So for the injection molding manufacturers, in addition to the need for a large tonnage of injection molding machine, but also need to have rich processing experience and knowledge reserve. On this basis, it is possible to better use of technology, processing to meet customer needs of beauty instrument shell products.

Appearance of the shell of the beauty instrument

In addition to strict requirements in the manufacturing process, independent quality inspection is also required. On the one hand, it is necessary to produce in strict accordance with the product drawings, and on the other hand, it is necessary to strictly control the appearance quality of the shell of the beauty instrument. If the product is found in the process of inspection of the size of the situation, it is necessary to timely repair or scrap treatment; If there are stains and scratches on the surface of the injection shell, it is necessary to deal with them again.

In addition, the color difference, corrosion resistance, adhesion and other inspection work after spraying is also an important part of the detection of beauty instrument shell injection process, so it is necessary to pay attention to each link, only in this way can reduce the errors in the production process, so as to get high-quality beauty instrument shell products.