Surface Grinding – The Ultimate Guide

One of the oldest machining technologies is surface grinding. Over the years, it has changed with the evolution of technology. As technology improved, so did grinding method.

And with time, different techniques have evolved, too. They include cylindrical, surface, centerless, and internal grinding. These four types all serve their purpose. Although our focus today will be on surface grinding.

Read on to find out more.

What is Surface Grinding Technique?

Surface grinding is a widely used technique done using an abrasive machine such as CNC machine. Industries prefer this technique as it helps provide precise dimensions.

One important component needed while surface grinding is the rotating abrasive wheel. Without it its impossible to achieve a smooth surface finish.

You can also use this technique to remove dirt or rust. It is popular in many industries like metalworking and job shops.

Now that you understand surface grinding let’s assess why you may need to use this technique.

Why Should You Grind Surfaces

In this section, we will look at why industries choose to grind surfaces.

• Performing grind surfacing helps provide a precise surface finish

This is possible because surface grinding effortlessly removes impurities in a controlled way.

• There are no limits while using surface grinding

The good thing about using surface grinding is that you are open to use any material you want. You can use plastics, ferrous and non-ferrous materials, and ceramics.

• It is cost-effective

It is a cost-effective solution when it comes to getting better surface finishing.

• It is compatible with automation.

Most industries’ dream is to have techniques that help improve production. Surface grinding helps these industries achieve this dream.

• Improved durability

By removing impurities on the workpiece, surface grinding helps improve the materials’ longevity and durability.

• You do not need a skilled operator.

You can easily surface grind manually or automatically. You do not necessarily need an operator if you run the machine manually.

From this section, it is evident that grind surfacing is a beneficial technique. However for this method to benefit you, you must pick the right type of surface grinder.

Did you know there are five types?

Let’s have a look at them;

Types of Surface Grinders

The five common types of surface grinders include;

1. Horizontal Spindle/Reciprocating Table

A common technique used in most if not all machine operations is the horizontal spindle. It can easily accommodate small and large work pieces as the surface grinders come in different sizes.

During the process the grinding wheel usually moves back and forth. For you to achieve this technique you need to place the wheel horizontally as it works its magic on the work piece’s edges.

2. Horizontal Spindle/Rotary table

The wheel is also horizontally mounted as it cuts its perimeters. For you to achieve the rotatory table technique you need to mount the workpiece in a way that it can easily rotate 360 degrees.

Notice that while using this method, the workpiece should be under the wheel head. Doing so helps the wheelhead easily do cross-feed movements.

3. Vertical Spindle/Reciprocating table

This kind of grinder is best when you wish to grind narrow and long castings. It is good to use when removing materials. For the vertical spindle to work it is best to always place the workpiece on the reciprocating table.

Doing so makes it easy to make adjustments when needed. Alternatively if you wish to achieve an index rotation you could place the workpiece on the rotatory table machine.

4. Vertical Spindle/Rotary Table

Note one property that makes this type of grinder unique is that you can use it to cut heavy metal or remove impurities on it. You’ll need segmented or cup wheels for this method to function well.

The other good thing about using this method is that their spindles can finish large castings.

5. Disc Grinders and Double-disc Grinders

As much as we classify disc grinders as a type of hydraulic surface grinding, in actuality, they are quite similar. This is because it also involves a great area of the disc and workpiece in close contact.

From its design, a surface grinder offer flexible grinding system. Usually, you can work on both sides of your workpiece.

Knowing these types will come in handy when using surface grinding for your product. However, choosing the right surface grinder is not enough to get outstanding results.

You’ll also need to choose a good grinding wheel to help you achieve your needs. So before you decide to buy your next grinding wheel, make sure to read this section.

What to Look For Before Buying A Grinding Wheel

The grinding machine has different parts that all play an important role. A grinding wheel is an important component of the grinding machine that always needs to be the right one.

If you wind up using the wrong wheel you may not achieve the best results. There are a couple of grinding wheels on the market. This way, it is important to look at a few factors before settling on one. They include;

· Material You Will Grind

You’ll need to know what you are grinding and assess if it is a soft or hard material. Knowing this will help you choose the right abrasive and grain type.

If the material you choose to use is easy to grind then you could settle for a durable grain. In the case where you end up with a hard material then a mild grain is a good option for you.

· Extremity of the Operation

Before choosing a grinding wheel always ensure that you always know the amount of grinding pressure you’ll use. This is because not all grinding wheels can handle the high extremity of an operation.

Knowing the severity of the project will also help you know the type of grain you’ll use. For a high-pressure operation, you’ll need a tough grain.

· Finishing that youNeed

It is important to know if you need a fine finish or stock removal. Understanding this need will make it easier to choose the right grinding wheel.

· Momentum of the Wheel

You need to know the operating wheel speed you’ll use for your operation. Knowing this will help you choose the right wheel specification and also know the wheel grade you need to choose.

You can use this equation to calculate the surface speed.

Surface speed = π×Diameter (inch) × RPM÷12

Surface Speed (M/s) = π×Diameter (mm) × RPM÷60000

Machine’s  Horsepower

This is an important factor that you should never overlook as it will guide you in knowing the type of hardness the wheel should have.

If the operation will use a high horsepower, then you’ll need a hard wheel. A softer-grade wheel will do the job if the horsepower is low.

Using these factors will help you in choosing the right grinding wheel. However, finding the right grinding wheel doesn’t solve the puzzle as there are more pieces to tackle such as which grinding method to use.

For some they get confused on whether to use cylindrical or surface grinding symbol. Knowing how these two compare will help you make the right decision. Let’s have a look at them.

 How Cylindrical Grinding compares to Surface Grinding

The simplest way to compare these two is by assessing the shape of the results. Surface finishing helps the operator to get a flat surface finish on the workpiece. On the other hand, a cylindrical grinding process will get the best round cut.

Here are a few reasons why industries may choose to use either of the two

Surface Grinding It is easy to specify the tolerance thickness when need be Achieving smooth finishing on flat surface is easier Recommended for both metallic and non-metallic parts You either choose to use automatic or manual operations

Cylindrical Grinding Perfect for producing very precise and outer surfaces A better alternative for processing hard materials This method is easy as you do not require heavy machines or hire skilled operators. Most cylindrical machines have high productivity rates as they can run for hours without breaking down.

 The method you wind up choosing solely depends on your needs, as they all offer different results and benefits. If you choose to use surface grinding, you’ll need to solve another puzzle before grinding the surface.

Let’s dive deep into it.

Tips to Consider when Grinding Surfaces

The following tips are facts you need to keep in mind before starting your grinding project.

• Make sure to assess the material you are grinding and the finish you want to achieve, as it will help you choose the right grinding wheel.
• The other tip to consider is the grinding parameters, which entail the wheel’s momentum. Evaluating this will help ensure that you get a quality surface.
• Always ensure that you have consistent pressure as it helps ensure that you get even surfaces.
• Make sure that you consistently dress the grinding wheel to help ensure it maintains its sharpness and effectiveness.
• Always keep a close eye when grinding the surface and occasionally check the surface finish, as it will help you know if you need to make adjustments.
• To ensure your safety, always ensure the working area is clean and free from any debris.

Observing these guidelines will reduce the chances of having a failed surface grinding project. Although these tips may not be of much help if you do not have an idea on how to surface grind. So, stick around to find out how the process starts and ends.

A Detailed Step-by-step Guide to Surface Grinding Process

Industries seeking to have their metallic or non-metallic materials have a smoother finish often settle with surface grinding. This is possible as the grinding wheel removes impurities such as an oxide layer on the material.

Before you start grinding a surface it is important to have a good workpiece material such as iron or steel. Choosing these materials is great as they do not block the grinding wheel.

Make sure that you have all the surface grinder components. They include a reciprocating table, an abrasive wheel, and work holding device. Lastly, there are occasions when you may need a lubricant to cool the machine.

Make sure to check the material you are working with, as it will help you choose the right lubricant. Once you cross-check that you have everything then you can start the process.

When you wish to grind a surface, you first need to mount the workpiece on the reciprocating table. After mounting the workpiece, you’ll notice that it will slowly moving across the grinding wheel.

Also, the workpiece is always in a back-and-forth motion until the desired finish gets achieved. Note that you’ll need to set the machine’s temperatures high when you intend to remove materials on the workpiece.

Although this excessive heat can affect the surface finishing so its good to introduce coolants here. Doing so will help ensure the machine remains cool.

You can as well use lubricants on the moving parts. If you do not know the lubricant you should use here’s a guide you can follow;

Recommended Lubricants in Surface Grinding Process.

There are a few times when you may need to use a lubricant to cool the wheel and workpiece. Using lubricants also helps remove chips. While applying the lubricant, make sure you apply it directly to the cutting area.

This will help ensure that the grinding wheel does not carry the lubricant away. Note that the type of lubricant you choose solely depends on the material you work with.

• Aluminum: Uses heavy-duty oil
• Brass: Will only use light-duty oil to cool the machines
• Cast iron: Synthetic oils and heavy-duty emulsifiable oil offer better cooling
• Mild steel: Heavy-duty water-soluble oil is a perfect lubricant
• Stainless steel: You can use heavy-duty emulsifiable oil; heavy-duty chemical and synthetic oil for this particular material
• Plastics: Plastic can use a variety of lubricants such as water-soluble oil; dry, heavy-duty emulsifiable oil; light-duty chemical, and synthetic oil

Knowing the right lubricant to use will always ensure that your machines are up and running in order to create a perfect workpiece. Although in most cases the workpiece created often differs from the original material. And in some cases, it can affect its properties. Let’s have a look at some of these effects.

How Surface Grinding Affects Material Properties

During the process, the material is often exposed to high temperatures, and due to these changes, it creates residual stresses. Also, the part’s surface is likely to form a hard crystalline form. This in turn will reduce the fatigue strength.

If you are surface grinding a magnetic material often it may lose its magnetic properties when exposed to extreme temperatures. Lastly, the materials are prone to corrosion.

Factors Affecting Surface Grinding Success Rate

· Speed of the Wheel

Always check the wheel’s RPM. Note that the wheel RPM always remains constant while surface grinding. In case the wheel RPM is high it may cause material burn.

Lastly, you need to assess the material you are grinding, as it will help you know the wheel speed you need to use.

· Feed Rate

This is the back-and-forth movement of the workpiece on the wheel. Having a faster feed rate helps remove impurities faster although it causes chatter marks. Therefore in order to get a finer finish it is best to use a slower feed rate.

· Depth of Cut

Having a deeper cut allows you to remove more materials although it can cause wearing out of the grinding wheel. So it is best to stick to lighter cuts as they will give you a fine and smooth finish.

· Type of Wheel

If you are grounding a hard material, wheels types  ranging from CBN, aluminum oxide, and silicone carbide can get used. Cork wheels are great options for operators who wish to burnish or polish their workpieces.

· Wheel Dressing

When you poorly dress the wheel, you are likely to lead to fast tears, glazing, and vibration. Also an, improper dressing does not create a good finish.

· Use of Coolants

Using coolants helps in cooling the wheel, and workpiece, flush chips, and prevent loading of the wheel.

· Work Holding

Always ensure that you securely mount the workpiece to improve accuracy and prevent chatter. You can use clamps, chucks, vacuum, or magnetic tables to achieve a strong work hold.

Choose an Experienced Personnel

Having a knowledgeable operator will help ensure that they choose the right parameters and ascertain great results.

Assessing these factors will help ensure your next grinding project is a success. But as we all know, everything has its limitations, and so does the surface grinding process. Let’s have a look at some of these limitations.

Limitations of the Surface Grinding Process

Here are some limitations for using surface grinding;

• You are likely to weaken a material when surface grinding under high temperatures. They are also likely to corrode or even lose their magnetic properties.
• When an operator is not keen on controlling the heat while removing material they may damage the surface finish.
• Surface grinding promotes the generation of an abrasive swarf. The lucky thing is you can effortlessly eliminate it by using coolants. Doing this will help prevent scratches on the workpiece.
• The other limitation of using this technique is that it exposes the grinding wheel to a lot of wear and tear. Which in turn forces the operator to use a lot of spindle power.

Although do not let these limitations sway you away from using surface grinding. This is because there are so many things you can achieve while using this type of grinding. They include:

How To Use Surface Grinding Method

Here are some key areas you can take advantage of surface grinding technique;

• You can use this method to get a well-defined surface

Surface grinding is an ideal method to use when you wish to have a reference surface due to its ability to produce distinct flat surfaces. Making it the best method to use when flattening valves, gauges, machine ways and bearings.

• You can use it to create an improved surface finish.

The abrasive grinding wheel helps remove imperfections on the workpiece. This, in turn, will help you achieve a polished finish.

• It helps achieve perfect shapes and profiles.

You can dress the grinding wheel with different profiles and create unique shapes for workpieces like cutting tools or gauges.

• Helps square blocks and remove stock.

Not only can surface grinding help in removing materials but it also helps in squaring up blocks. This feature makes it a favorite for operators using rough machines.

• Helps clean up welds and castings.

Surface grinding helps remove burrs, armoury imperfections, welds, and flashes from casting.

• You can use it to deburr holes and edges.

The edge of wheel makes it possible for the operator to either deburr holes or even create a radius on the edge of the workpiece.

Conclusion

If you are looking for highly efficient and affective surface grinding service machines, TSINFA, has the best solution for you. Whether you want to upgrade or invest in a new machines, we will help you get the best surface grinder for your business – contact us now.

More Resources:

Surface Grinding Machine – Source: TSINFA

Surface Grinding – Source: WIKIPEDIA