Polyurethane injection machine

Types of Polyurethane Injection Machines

Polyurethane injection machines serve different markets because they have been designed to meet different needs and applications. The following types are popular amongst users:

• Low-Pressure PU Injection Machines

  Low pressure is the predominant way to inject urethane foam into molds. This method involves using a pump to inject mixed material under one to two ounces per square inch (oz/in2) of pressure. It is cheap to set up and also helps to create better quality parts. Better quality here means pieces that are not overly dense, pieces with fewer internal stresses, and those that have a decent surface finish. Additionally, pumps using this method could be air, gear, or hydraulically driven.

• High-Pressure PU Injection Machines

  High-pressure PU injection machines use mixed materials that are injected into closed or open molds using about 1,500 to 2,000 psi (pounds per square inch) of pressure. This method works well with elastomers and is ideal for creating products with more specific qualities like precise part tolerances, faster production rates, and quicker curing times. However, another thing that the manufacturer has to consider when using this method is that the mold releases used have to be low.

  High-pressure machines generally have hydraulic drives and are more expensive than low-pressure ones. There are early, delayed, and total readings on hydraulic drives, and all of those systems have to be considered before choice or use.

• Touchscreen-controlled PU injection machines

  These machines provide customizable polyurethane production with a user-friendly interface. They enable precise adjustment of parameters like injection speed and volume, pressure, temperature, and time. The touchscreen display ensures accurate formulation, and recipe storage simplifies setup for different production runs. Controlled machines enhance efficiency, reduce waste, and ensure consistent product quality.

• Separator Vacuum PU Injection Machines

  Vacuum separator machines simplify mold making by allowing users to inject materials between two separating plates. The plates used here are usually made from aluminum, but other materials could be used, depending on desire and specification. Operators can easily remove the molds after the material has cured. This makes mold production a lot easier and faster. These machines also use a vacuum to hold the mold in place while the material is injected.

Specifications and maintenance of polyurethane injection machines

Specifications

• Flow: 1-15kg/minute. The flow is affected by the output of the pump, the mixing speed, the viscosity of the material, the pressure, the temperature, etc.
• Pressure: 15-80Mpa. The higher the pressure, the more the materials are mixed and compacted to reach the desired density, volume, and expansion.
• Mixing Speed: The ideal mixing speed is 3000-6000rpm. Speed influences foam structure and reaction time.
• Capacity: The tank sizes for A-side and B-side liquids are usually 50-100L. However, special requests for smaller or larger tank sizes can be fulfilled to suit individual needs.
• Weight: 300-800kg. The weight varies depending on specific configurations, components, functions, etc.
• Dimensions: Length x Width x Height: approximately 1-2m x 0.5-1m x 1-1.5m. The dimensions of the machine vary according to the design, model, and type of machine.

Maintenance

• Cleaning and care: Clean the external surfaces and keep them free of dust and dirt. This prevents the materials from getting mixed up. Regularly clean the injection nozzle, mixing head, and discharge port to avoid blockages.
• Lubrication: Regularly lubricate the moving parts and guide rails to reduce friction and wear. Pay attention to lubrication for all types of pumps and valves.
• Electrical system inspection: Check electrical circuits, terminals, and connectors in DC and AC electrical systems to ensure that they are secure and free of oxidation or damage.
• Hydraulic system inspection: Check hydraulic hoses, seals, and valves. Ensure no oil leakage is present, and the pressure is steady and reliable.
• Control System Inspection: Regularly check and calibrate sensors and controllers to ensure accurate control of parameters such as temperature, pressure, and time.
• Parts replacement: Replace wearing parts, such as seals and filters, on a regular basis to ensure the reliable operation of the machine.
• Safety device inspection: Regularly check the safety devices of the machine, such as the emergency stop switch, safety covers, and overload protection, to ensure that they are functioning properly.

Scenarios

Machines for polyurethane injection are beneficial in construction, furniture, automotive, packaging, and footwear industries.

• In the construction industry: They create insulation boards, panels, and pipes. Additionally, they make waterproofing products and sealants to prevent water ingress and ensure durable structures. Also, the machines make construction adhesives for easy bonding.
• In the furniture industry: The machines are used to produce upholstered furniture such as sofas and armchairs. Also, they create furniture products that require cushioning and padding, such as mattresses.
• In the automotive industry: The machines create car seats, door panels, and dashboards. They also make soundproofing and vibration damping components. Additionally, the machines are used to produce gaskets and seals for automotive applications.
• In the packaging industry: They create protective packaging such as inserts, cushioning, and padding for fragile products. They are also used to produce packaging solutions and clamshells for electronics and consumer goods.
• In the footwear industry: polyurethane injection machines make shoes with soft and elastic soles such as sneakers, walking, and running shoes. They also create shoes with good shock absorption properties and sporting footwear.

How to choose polyurethane injection machines

When buying a polyurethane injection machine, buyers should consider the intended application or use. The machine-type requirement can vary depending on the application. For example, a walk-behind injection machine is suitable for small tasks, whereas a spray machine works best for large projects like insulation or roofing. Buyers should also consider the tank size of the PU injection machine. The tank capacity determines how frequently the machine will need to be refilled during operation. A larger tank will allow for longer continuous operation but may make the machine heavier and less portable.

Another important consideration is whether to buy a manual or automatic polyurethane injection machine. Automatic machines offer more consistent performance and are easier to operate but may be more expensive. Manual machines are less costly but require more operator skill and effort to achieve good results. Also, consider the weight of the machine. Heavier machines are more durable but, depending on the weight, may be more difficult to maneuver on the job site. If portability is important for the intended application, choose a machine with the right weight for the task at hand.

In addition, look at the safety features of the machine, such as the emergency stop buttons. It's important to operate safe equipment. The cost of the machine, including the warranty and any maintenance required in the long run, should also be considered before making a purchase. With all these things in mind, buyers can choose the right polyurethane injection machine.

Q & A

Q: How does a polyurethane injection machine work?

A: The machine works by simultaneously mixing two-component elastomers, foaming agents, and isocyanates through a high-pressure impingement mixing process. The chemical reaction initiates the expansion of the material, creating a foam that fills the cavity of the mold.

Q: What are the benefits of a polyurethane injection machine?

A: The machine provides benefits such as production flexibility, faster cycle times, waste reduction, and high-volume efficiency.

Q: What types of products are made with a polyurethane injection machine?

A: The machine is used to manufacture insulated panels, automotive parts, sealants, gaskets, refrigerator, and freezer components, among other products.

Q: Can a polyurethane injection machine handle multiple materials simultaneously?

A: Yes, certain machines can process more than two materials concurrently by utilizing specialized mix-heads and injection units.