Shot Peening

Precision Shot Peening Services In The UK

Preserving the life of your machinery and ensuring it runs effectively and efficiently is crucial in any successful business. There are many processes that allow this to be achieved, shot peening is one of the most effective and cost efficient methods in doing so. However, a question that is often posed is what actually is shot peening? Despite it being an extremely popular engineering method it is all too easy to get lost in the technical terms and jargon. That is why here at MNB Precision we have composed a detailed guide for you to answer all those questions. Read on to find out!

What is Shot Peening? Why Consider? Machinery Used

Our Shot Peening Machines

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What Is Shot Peening?

Peening is an engineering method for enhancing the surface of various different materials. It provides a cost-effective and practical way to extend the operational lifespan and performance of the main construction parts. It is a controlled process used to create a compressive residual pressure layer and modify the mechanical property of various metals. By introducing residual stress in the surface, you can prevent cracks from generating on stressed alloy components. The pressure created on the material surface is developed by different manufacturing processes such as milling or drilling.

 

How Does Shot Peening Work?

Shot peening is achieved by accelerating tiny beads, ‘shots’, directly to the surface. These ‘shots’ are metallic balls or glass beads. The force at which they are shot is sufficient to create new shapes. Each piece of shot acts as a mini peening hammer forming dimples, for this to happen the material must yield in tension. During this process, compressed stress is generated as the impact of each shot produces indentations which stretch the surface; the material beneath those dents resists and creates an area of stress. When the ‘shots’ hit the surface and generate the small indentations, the component becomes encased in a stressed layer. If you are looking for the most economical and practical method of ensuring surface stress then shot peening is the best manufacturing method there is.

 

How Is Shot Peening Applied? 

Also referred to as shot blasting, this engineering method is extremely effective in enhancing the surface of various materials. The shot, in shot peening, is known as a spherical material, and each bead hits the surface of the product material. The high impact of the shot creates a dimple. Now imagine hundreds of shots fired at the material to create a precision shape or crater. The dimples created are actually making the surface material stronger and more resistant to cracking. Each application of shots is a thought out and specified prior to processing. When the parameters have been established, the depth and size needed then the work can be tested and any repeat work needed.

 

Cold Hammering

Shot peening is similar to sandblasting as it is sometimes referred to, however, unlike sandblasting, peening has less dust production. Shot blasting a surface is often used for aircraft repairs as it can relieve tensile stress built up from grinding. The different types of shot beads available are spherical cast steel shot, ceramic bead, glass bead or rounded cut wire these all give different finishes. Peening is commonly used to impart additional material resistance. It can be used for the following applications:

• Crankshafts
• Gear wheels
• Connecting rods
• Automotive gear parts
• Coil springs
• Turbine blade (Aircraft)
• Airframe components
• Suspension springs
• Medical implants

At MNB Precision we use a wide variety of different peening machinery. Within the precision engineering industry, there are thousands of different machines that can all deliver different results. Here are just a few different shot peening machines that can be used:

• Rotary index machines
• Automated rotary machines
• CNC machine
• Continuous machine
• Pressure machine
• Suction machine
• Fine steel peening machine

If you have more specific needs, we will work to accommodate. We are continuously working to increase both our capacity and capabilities to meet market demand; as such we can cater to the needs of leaders in the industry.

Why Consider Shot Peening?

Shot peening can help to prevent fatigue cracks, corrosion, deteriorated strength and premature fatigue that can be caused by machining and form metal parts which also creates internal stress concentration. It also helps to prevent crack formation and growth since typically fatigue cracks generally begin at the imperfection on the surface of the material. The benefits are not only limited to being able to prevent structural weakness and cracks. They also extend to facilitating the building of stronger and harder components like gear cogs that have been shot peened after carburizing with a hardness level above Rockwell 60RC that can be used in fatigue and shock applications.

Peening also helps to allow existing designs to function at higher stress level and enhances lubricity when used on bearing surfaces and gear teeth. For cosmetic requirements, it is able to produce more uniformly textured surfaces for special coatings and adhesion and also helps to harden matting surfaces preventing galling and fretting. There is a variety of different machines that can be used for different applications and on different parts with different functions depending on the end product and the reasons.

There are also different types of parts that can be subjected to shot peening. However, gears have always been the main beneficiaries of the process because they typically work under stress most of the time and could benefit from harder properties. It is important to remember that for the best results it is important to match the right material to the right machinery for the right reasons. Various advantages include:

 

Advantages Of Shot Peening:

• It reduces stress corrosion splitting
• It can prepare components for plating
• It straightens fragments that were deformed when manufactured
• It reduces casting permeability
• It can alter part dimensions
• It will improve oil retention

As mentioned above it is extremely important to match the right material to the correct machinery to achieve the best results. Below are examples of the various shot peening machinery we have available.

Shot Peening Machinery

Machines Used In Shot Blasting

Most machines used in peening & blasting are available here at MNB Precision. The type of machine used will depend on your industrial needs. To strengthen a piece of material, singular or multiple nozzles are pre-set at specific angles and at a certain distance depending on what the desired finish is. Various machinery is better suited to different industry needs.

• Rotary Index Machine:

Rotary index machines are made to provide precision blasting for complex parts. The rotary tables offer high volume production of complex shapes with multiple stations for loading and unloading to maximise production volume.

• Automated Rotary Machine:

An automated rotary machine is where precision peening is done with automation. Automated machines are designed to meet the high volume of production.

• CNC Shot Peening Machine:

CNC machines are Computer Numerical Controlled machines used for precision engineering giving even and exact finishes.

• Continuous Shot Peening Machine:

A continuous peening machine is ideal for blasting, coating and spraying. A 360 design allows constant and even finishes to parts.

• Pressure Shot Peening Machine:

A pressure shot peening machine can give high depth to components, and blast nozzles are positioned with precision to ensure efficiency.

• Suction Shot Peening Machine:

A suction shot peening machine is used to create parts that require a less aggressive surface and ensures an even finish to an entire surface.

• Fine Steel Peening Machine:

To improve the strength of materials, fine steel peening machines are used. They can create fine dimples on a surface, the compression strengthens the part.

 

Features Of Shot Peening Machines

There are many different features of shot peening machines but some of the main features include: fixed or travelling guns depending on the type of machine, flexible loading and unloading mechanisms, adjustable media and air pressure, gun rods, holders and locking bolts. Typical applications for shot peening are:

• Turbine Blades
• Airframe Components
• Aerostructure ribs
• Drill rod thread (Gas & oil industries)
• Seal Rings
• Medical implants
• Springs

So there you have it, our complete guide to shot peening and all its applications. For more information on our services or any other precision engineering services we provide do not hesitate to contact us!