A surface grinding machine is needed to create smooth accurate finish on materials that are either metallic or non-metallic. This machine makes use of a round stationary abrasive grinding wheel that rotates as the feed table runs in a left and right motion.
The amount of material that needs to be removed is determined by simply touching off on the work feeding the grinding head and grinding wheel rotating downwards to a certain distance.
Normally surface grinders have the ability to grind within .0001 – .0002 but since they are not created equal, it’s important to note that the cheaper models may not have very good tool room accuracies.
They can, however, be used to sharpen punches and dies as well as to handle some repair shop work. High end models have better quality spindle bearings and other components to achieve tool room accuracies.
An Overview of the Surface Grinding Machine
First, you need to select the correct grinding wheel. There are a variety of wheels that you can choose from:
- Alloys That are Nonferrous
- 400 Series Stainless
- High Speed Steel RC 50-68
- Soft Steels RC 30-45
- Ductile & Gray for Cast Iron
- 300 Series Stainless
In any of the above categories, you have to know the wheel type by determining if you need light stock (.001), moderate (.002-.004) or heavy (> .004) removal characteristics. Also, you’ll got to choose a Grit size.
Forty six grit being for general purpose, sixty grit for commercial, eighty grit for fine finish and one hundred twenty grit for super fine finishes.
After choosing the proper wheel, visually examine it for any cracks or damage. If none is found, install the wheel, tightening the left-hand spindle nut rigorously using wrench.
See to it that you replace the guard covering the wheel, place safety glasses on then flip the spindle on. Step away and allow the spindle to run for about a minute.
After you have dressed the grinding wheel remember not to turn off the spindle since doing so would require the wheel to be dressed once more.
You are currently able to dress the wheel employing a single purpose diamond dressing tool that’s placed by means of a magnetic chuck. A minor amount of grinding wheel ought to be dressed off of the diameter so as to form the wheel run concentric.
Place the diamond dresser below the rotating wheel and produce down the grinding head rigorously therefore it simply touches the dresser. Using the cross feed, diamond dresser should be swept across the rotating wheel.
After you feed the grinding head down to as low as .002 you need to sweep the diamond dresser across the rotating wheel. Repeat the process several times until the face of the grinding wheel is clean.
After the wheel is dressed and is operating in circular direction, you’ll then be able to gently turn off the work. Now it’s time to set your “zero” on the down feed handle, slightly raise its head to clear work then the cross feed handle to distance the grinding wheel from your work.
Then you need to feed the grinding head down to no more than .005. The fabric quantity being removed should serve as your basis for how far you can feed the cross-feed for every pass.
Surface Grinding Benefits
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- You can grind abrasive or hard materials.
- It has very good dimensional accuracy.
- It produces high finish textures.
- Tooling is more affordable.
- It can be performed automatically.
Surface Grinder Safety Rules
To avoid injuries, follow the security precautions for using surface grinders listed below:
- If the grinding wheel is allowed to go over the maximum safe speed, it’s going to disintegrate and may injure the operator.
- Always wear safety goggles when dealing with any grinding machine operations.
- Before mounting, inspect the grinding wheels for cracks.
- Do not operate the machine at a speed higher than the recommended speed in your instructions manual.
- Do not modify anything once the machine is running.
- Do not go over the recommended cut depth for the machine particularly the grinding wheel.
- Before turning the machine off, remove the workpiece from the grinding wheel.
- Always use the proper wheel guards.
The Big “Do Not” About Surface Grinding
Here are the most important DON’Ts you need to know about when it comes to the use of surface grinding machines and other similar equipment.
Utilizing Incorrect Power Sources
This may be obvius enough but it bears repeating here. See to it that the unit you are using has the correct power source.
Grinders that are engine-powered are normally best option when it comes to outdoor applications, since these units won’t work at an outdoor location where there is a lack of electrical outlets.
On the other hand, machines that are electric powered won’t work at indoor locations which are missing the correct electrical power. The ideal solution would be a propane-powered machine.
Units that are electric powered usually have high voltage and amperage requirements, which is why it is important to know whether your equipment needs a 230-volt or 115 volt power source.
You also need to be aware if it needs a 20- or 15-ampere circuit. You’ll know this information simply by looking at the electric motor data plate.
If the machine requires an extension cord, it should be measured to allow adequate electrical flow based on the specifications of the motor. Pick a cord that is longer than what is needed, as cord length impacts electrical voltage loss and resistance.
Manufacturer help desk representatives often receive calls from operators who are not happy with surface grinder’s outcome. But the thing is, their dissatisfaction often stems from the use of an improper attachment.
For example, one among the widespread mistakes is making an attempt to use silicon-carbide stones to get rid of grind floor coatings.
The stones can work briefly before their pores clog with material. When this happens, they are no longer effective. You’ll need scraper attachments for this. Conversely, scrapers won’t work once making an attempt to eliminate concrete.
In the last few years, many kinds of attachments have been created for various applications, and most makers post data on their websites concerning the right use of these attachments. Sadly, a lot of end users fail to teach themselves and, as a result, fail to realize the results they desire.
Lack of Maintenance
Low-speed surface grinders square are easy to operate, use and maintain. Apart from regular engine maintenance for units that are gas-powered, there aren’t several parts that may require servicing.
However, due to the abrasive concrete that mud grinders make, these things will require some crucial lubrication to be able to work efficiently for a long time.
One of the most common things that go unnoticed is to lubricate the transmission bearings. The issue exists due to the lack of maintenance from personnel in getting rid of excess concrete mud accumulations in the bearings.
Over time, the grease fittings will no longer be visible, and dirt will keep on contaminating the bearings. This will eventually lead to total bearing failure, which can consequently damage transmission parts that are very expensive to replace.
To combat this issue, a few manufacturers equip their machines with a remote lubrication system that is designed to make maintenance much simpler.
However, even this may not be enough. So always see to it that the bearings are properly lubricated within schedule. Another important maintenance requirement is the attachments of the surface grinder.
These things are vital to your operational success, so see to it that they wear equally and replace them when you see that the contact surface is close to the attachment discs. The attachments varies in service lifespan so it’s important to have an idea of how long each one will last.
For example, one might estimate that a set of carbide grinding stones could last as long as 5,000 square feet, but a diamond system might be able to cover as much as 50,000 square feet before it will require replacement.
Additional Don’ts for Surface Grinding
- If the grinding wheel was subject to impact (ie it was dropped), do not use it.
- Do not use a grinding wheel that has any abnormality.
- If the grinding wheel’s hole diameter does not match the machine, avoid forcing the wheel into the machine.
- Do not go beyond the maximum operating speed as indicated on the grinding wheel.
- Do not over-tighten the nuts when mounting onto the flanges.
- Do not start the machine prior to installing the cover of the grinding wheel.
- Do not press the workpiece against the wheel using excessive force.
- Do not touch the grinding wheel directly when rotating.
- Don’t stand in front of the wheel during a test operation.
- Do not place the grinder onto a workpiece, floor, table or any surface before the grinding wheel has stopped completely.
- Unless you have received the necessary training, do not change the grinding wheels. You should also not perform any test operations.
- Don’t use the machine in an area where there is a risk of explosion.
Look at Your Preferred Support
As with any other operations that make use of machines, changes in the set up should be avoided as much as possible. This can be achievable if all flat ground surfaces are on the same side as the part and are matching.
Remember that the magnetic chucks are primarily designed to hold down components as the operator works on surface grinding. If the part is compatible with the magnetic chuck, operating the machine becomes easier and you become more productive.
The magnetic chuck requires a magnetic (ferrous) material as well as a flat seating surface that is situated opposite the bottom surface.
Make sure the ground surfaces are way above any obstructions because they need to run as continuously as possible and should be securely supported as well.
The use of surface grinding machines require skill and common sense. Make sure to practice and understand all the safety guidelines to avoid any injuries. Whether you are the operator or you have a team of operators, knowledge of the basic precautionary guidelines will certainly come in handy.