Category Archives: Manufacturing & Tooling

What Is Transfer Molding?

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Many builders ask the question, “What is transfer molding?” Transfer molding is a manufacturing process used to shape materials, typically thermosetting plastics. The process entails heating the material and then transferring it into a mold cavity where it is allowed to cure and harden, forming the desired shape. This technique is used most often for the production of complex parts with high precision.

Transfer molding is considered a complex process due to its design and need to accommodate intricate features. Achieving precise results with complex parts presents a challenge requiring careful control, which may result in the need for specialized tooling. While the basic concept of transfer molding is relatively straightforward, the fine details and focus on precision make transfer molding a complex procedure.

What Is Transfer Molding Used For?

Transfer molding is a versatile manufacturing process used in the production of various products across multiple industries. Transfer molding is often used for the manufacturing of:

  • Electrical components, such as switches, connectors, circuit boards
  • Automotive parts, such as specialty seals, gaskets, dashboards, and vibration isolators
  • Medical devices, such as syringes, housing for implants, disposable equipment
  • Consumer goods, such as toys, grips, keypads, housings for electronics
  • Rubber products, such as grommets, washers, O-rings

The Transfer Molding Process

Transfer molding is a versatile manufacturing process primarily used in the production of thermosetting plastic and rubber components. This form of molding implements characteristics of both compression and injection molding. The process of transfer molding requires that a material be heated and cooled so it can obtain the desired shape. The basic process consists of a few simple steps:

  1. Heat the material: Transfer molding begins by heating the molding material. The molding material in transfer molding is typically a thermoset resin.
  2. Clean and coat: The mold is cleaned and coated with a releasing agent to prevent parts from sticking to the mold. The mold is then closed and tightly secured.
  3. Transfer: The heated resin is transferred from the heating chamber to the transfer pot. Pressure is applied using a plunger housed in the transfer pot. The application of pressure causes the material to take the shape of the mold cavity.
  4. Cure: Pressure is applied to keep the mold closed in order to cure the resin. For this step to be done successfully, appropriate curing time and temperature should be maintained.
  5. Trim: After the material has been shaped and cured, the mold is opened, and the finished product is removed from the machine. Each piece removed from the mold is checked for defects, and any excess material discovered is trimmed from the product.
  6. Ensure Quality: In addition to the machine operator checking for defects, a quality technician follows a process to ensure quality by performing quality checks and inspections.
  7. Repeat: The process is repeated to create identical components for each cycle.

Benefits of Transfer Molding

In addition to transfer molding, injection and compression molding yield similar results. Neither is superior to the other; each has its benefits and drawbacks. In transfer molding, the benefits include:

  1. High Cavity Count: The tool responsible for creating the shape of the component can create hundreds of identical cavities in a single cycle, depending on the size of the component.
  2. Flexibility: Transfer molding is unique in its precision. This precision allows for sharper edges, reducing the need to de-flash components removed from the mold.
  3. Short Cycle Time: Transfer molding offers tighter tolerances and more detailed parts largely due to its short cycle time. This characteristic also provides more consistency.

The Drawbacks of Transfer Molding

  1. Economic: Due to the complexity of transfer molding, tooling can become costly.
  2. Waste: Scrap and waste material accumulates at higher volumes than traditional methods. Scrap is not reusable due to the material used.
  3. Maintenance: Transfer tools typically require more frequent maintenance than other molding methods. Cleaning tools can be time-consuming and sometimes requires specialized equipment.

Specialty Seals in Escondido

Transfer molding is a versatile and efficient process that is used in the manufacturing of a wide variety of useful products. With its reliability and effective results, transfer molding is an essential practice for those involved in the manufacturing process.

How Seals Allow Pumps to Work

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Pumps are devices that move liquids or gasses by mechanical action. For the pump to work, it needs to be sealed completely tight to avoid leaks from occurring. In the past, pumps were sealed using rings, however rings were not effective in protecting the device from leaks. Today, most pumps are sealed by mechanical pump seals that are more competent in preventing leaks from happening.

Benefits of Seals

Leaking is the primary issue that is addressed by seals. The most obvious benefit of seals is that they allow pumps to function leak-free. So, if you are still using packing seals, then it is time that you switched to mechanical seals. Below are the benefits of mechanical pump seals.

• Having less fluid loss in a machine means better savings in terms of repair work due to pump failures. Moreover, they reduce the number of hazards that can put the lives of the pump operators in danger. Less leakage means fewer incidents of falling and slips due to the wet floor. It also reduces the potential of harmful emission, if the pump is housing toxic chemicals.

• Pumps do still have leaks, just not visible leaks. Experts approximate “healthy” and acceptable leaks to half of a teaspoon a day under normal operating procedures. Most machines will recapture the lost air and condense it.

• Seals can adjust to different faces of wear as they come with inboard springs. This reduces the necessary daily maintenance that needs to be done for the seal to work optimally.

Elements of A Seal

Seals allow the pumps to work by reducing downtime caused by leaks. They are commonly applied to contain any liquid or gas within a vessel where there are rotating shaft and a stationary housing. But how do seals protect the pump? Simple, they comprised of elements that would protect the machine against leaking. Below are the elements of mechanical seals.

• A set of primary sealing faces: A mechanical seal is made up of a set of lapped faces to minimize leaking. Different faces are made from different materials such as carbon-graphite and ceramic to prevent them from adhering to one another. Different materials are made so that they can perform different functions. For instance, one face of the housing is held stationary while the other one rotates along with the shaft.

• Static seals: Mechanical pump seals also come with a set of static seals like V-rings or O-rings to provide secondary protection against leaks.

• Spring: To create face contact, seals often come with a spring member which include either single or multiple springs.

• Other hardware: Seals are also made from other hardware which include gland rings, shaft sleeves, compression rings, pins, and collars.

Things to Consider When Looking for Seals

There are different mechanical pump seals out there on the market, but before you decide on which one to get, there are three important things that you need to remember when looking for mechanical seals.

• Seal faces need to stay together. If they open, leaks will occur thus allowing solids or contaminants to enter between the faces. Entry of contaminants will likely destroy the lapped surfaces not only of the seal but also the pump.

• The seal materials should be compatible with any fluids that are being pumped through the system. These include cleaners, solvent, and steam. Using fluids that are not compatible may destroy the seal by disintegrating its components and cause leaking in the pump.

• Mechanical seals have a good seal life. They expire once the carbon face is worn out which usually happens after a long time.

How Seals in Pumps Work?

Mechanical seals are watertight fittings that are located between the fixed part of a rotating device and a shaft thus they are commonly used in pumps. It is important to stress the water-tightness of the pump. This is achieved using a fine fluid or film that is located between two friction faces to prevent the remaining fluid from passing. The film also works as a lubricant thereby reducing the wear and tear between the two lapped faces. With a mechanical seal, the pump can work naturally without the fear of any leaks.

Seals provide damage-free and leak-free performance for almost any solution. Thus, understanding the science behind it will allow you to optimize the use of the seal based on its design.

For additional information and resources regarding the families of rubber and plastic sealants, machinery, and laboratory testing, contact Real Seal today.

Maintaining Hydraulic Components

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How To Maintain Hydraulic Components

Proper maintenance of a hydraulic pump is crucial for reaching maximum pump efficiency. Every component is reliant on another, so if just one component is damaged, the others will be damaged as well. Regular maintenance is necessary to prevent damage from occurring or getting worse.

Contaminants and Moisture

 

Prevention is the best way to properly maintain a hydraulic system. This means taking the steps necessary to keep contaminants out of the system (…if not, the performance of your system will suffer due to a number of factors):

  • Clean the area around dipsticks, fill plugs, and hydraulic filters before removing them to check or change hydraulic fluid. Make sure that hydraulic fluid containers are tightly sealed when stored. Pour the fluid directly into the system.
  • Change the fluid and filter after the first 50 hours of use. The manufacturing process may allow contaminants to enter the hydraulic system. Changing the fluid after 50 hours will eliminate these contaminants. From there, change the hydraulic fluid and filter at regular intervals according to the directions in the owner’s manual.
  • Check the oil before each use. Ensure that the fluid is in good condition, and that fluid levels are at a sufficient level. If the fluid is foamy or milky, there could be a leak where air is entering your system, causing jerky and slow hydraulic operation. Insufficient levels of oil will cause severe damage to the pumps.

Air within the system carries moisture. When the system cools down following an operation, the moisture will condense and mix with the hydraulic fluid, resulting in the milky appearance mentioned previously. Test for water by pouring a 1/8 cup of hydraulic fluid into a metal can, then heat it with a propane torch. If you hear popping or crackling, the fluid has water and must be changed immediately.

Check the temperature of the hydraulic fluid often, for signs like the oil being too hot to touch, or a burning smell. These symptoms point to a problem with the cooling system or pressure level. Inspect the hydraulic oil cooler or reservoir, making sure that they are clean. Remove dirt and other debris inhibiting airflow surrounding them. If the fluid is too hot for an extended period, the fluid will break down and won’t be able to lubricate properly.

Pumps

Pumps should be inspected for obvious external wear and damage, as well as cavitation. Cavitation  occurs when the the pump does not receive the necessary amount of fluid from the reservoir. Follow these steps every 50 hours:

 

  • Listen to the pump while the hydraulics are in operation. Rattling or a sound similar to marbles or rocks bouncing around the pump is a sign of cavitation. Shut the system down immediately if you hear either of these sounds.
  • Check the fluid level and filter if they are limiting or restricting the flow.
  • Examine for previous modifications to the reservoir, inlet lines, or pump. Alterations to these components will affect the pump inlet flow.
  • Leaks, bends, pinching, and other discontinuities will restrict the flow. Regularly clean your system’s strainer if you have one.

Cylinders and Motors

Cylinders have seals and rings which may be damaged by excess pressure and contaminants in the fluid. Check that your hydraulic fluid is clean, and inspect where the cylinder rods move in and out of their housing for leaks. Cylinders should not have dings, dents, and other kinds of damage, which will allow fluid and pressure to escape.

An attitude of prevention is essential for protecting your O-rings. Learn more about four ways to prevent seal failure here.

O-rings are susceptible to a variety of elements, including UV rays, temperature, and humidity, so they must be stored in a very particular way. Real Seal has covered proper O-ring storage here.

Valves

Valves may be abraded or may leak internally, which will result in low hydraulic pressure. Contaminants may become lodged in the valves and restrict the flow. Maintain clean hydraulic fluid to ensure properly-functioning valves.

Other Components

Hoses, lines, fittings, and couplers must be inspected for damage. Hoses and lines may be dented from falling tools, contact with other equipment, and a number of other factors. Lines should be inspected for cracking, cuts, or dents, which will restrict the flow or leak pressure. Hoses may be damaged in the same ways, in addition to overheating, extended wear, and defective manufacturing. Hoses may also be internally damaged, causing pieces to contaminate the system. 

Buy Your Hose Components From an Industry Leader

Purchasing quality components will help prevent damage and the need for repairs. Contact Real Seal, and our team of experts—including an in-house chemist and technical staff—will help you purchase the right seals and components to keep your hydraulic system running smoothly.

The 5 Must-Read Articles About Pump Efficiency

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Ensuring that a centrifugal pump is running as efficiently as possible requires extensive knowledge of what makes an efficient system, and what factors create efficiency. These five articles are essential for any user of centrifugal pumps.

1. What Is Efficiency?

Efficiency in a machines is defined as how well it converts energy from one form to another. For example, if a machine receives one unit of energy and outputs a half-unit of energy, the efficiency of that machine would be 50%. Unfortunately, the English system of measurements makes efficiency calculations more complex than this example. Read more about efficiency and the use of constraints here.

2. Specific Speed

Specific speed is a confusing subject that people easily get hung up on. But by considering specific speed as an index number to predict pump characteristics, it can be somewhat easier to grasp. Read more about specific speed and how it can be used to select the right pump, and even predict premature failure.

3. The Power of Wear Rings Part Two: Efficiency

Metal wear rings can actually produce a substantial decrease in efficiency, even when they are reduced to the minimum clearance. Unfortunately, metal rings cannot experience a clearance reduction below the minimum without the risk of pump seizure. Read more about how metal wear rings limit pump efficiency here.

Pumps: HP, RPM, and Energy Efficiency

Reducing a pump’s operating speed can help extend the life of its motor and bearings. Even the pump seals will have a longer life span, and the damaging effects of abrasives are reduced. Read more about reducing operating speed to save money on maintenance and reduce downtime.

Gain Efficiency With Volute Design

In radial machinery as well as other applications, a volute is meant to transfer flow from an annular cross section to an exit pipe. Or, a volute might be reversed in a turbine; there are many variations on how this part is used. Read more about the many uses of a volute here.

For even more information about pumps and their components, speak to the experts at Real Seal.