Manufacturers and industrialists know that when you’re working with aluminum on a regular basis, it’s imperative that you have at your disposal a number of machining techniques to work your metal to the exact shape and design that you want. This applies whether you will be working the material in house or contracting out the job to a third party. For instance, when you need to grind aluminum sheet or plate for an application, having a variety of grinding machines and blades at your disposal is essential.
This is because aluminum, despite its popularity and versatility compared with most other metals, is one of the most difficult materials to grind. If you don’t know what you are doing, grinding aluminum can cause major problems. Luckily, Clinton Aluminum is here to help.
What Does the Grinding Process Entail?
Grinding is a cutting method that involves the use of a grinding wheel to abrasively machine the material that you wish to cut. In manufacturing and tool making there are a wide variety of grinding machines and methods that can be used on many different materials, including metals such as aluminum and stainless steel.
Grinding is recognized for producing very fine finishes and accurate shapes, while also having the ability to rapidly cut large volumes of metal in mass production contexts. In general, it is better suited for cutting very hard materials than other forms of machining and traditionally was one of the only practical methods of cutting materials such as hardened steels. One reason it is commonly used with plate and sheet is its ability to make very shallow cuts, for instance reducing a shaft’s diameter by half a thousandth of an inch.
While it might not seem like it when first encountered, grinding is a true metal-cutting process. The way it works, at the microscopic level, is that each grain of the abrasive material serves as an individual cutting edge. As the grinder is applied to the material to be cut, the abrasive shears tiny chips. However, grinding is often thought of as a separate category from cutting and is referred to as such on shop floors.
What Are Some of the Different Grinding Methods and Tools?
In order to accommodate the wide variety of materials that need to be ground, a host of machines and methods have been developed over the years, each designed to handle a particular type of job. The machines themselves can range in size from handheld power tools such as angle grinders and die grinders to expensive industrial machines and bench grinders.
One of the most common methods is known as surface grinding, which uses a rotating abrasive wheel to remove material and create a flat surface. Typical tolerances that are achievable with surface grinding tools are ±2×10−4 inches on a flat material and ±3×10−4 inches on a parallel surface. A surface grinder is made up of an abrasive wheel, a work-holding device (referred to as a chuck), and a reciprocating table.
Cylindrical grinding is used, as the name suggests, to grind cylindrical surfaces, such as on poles and shafts. The piece that is being ground is mounted onto the machine and rotated by a device known as a center driver. With most machines, it’s possible to rotate the abrasive wheel and the workpiece separately and at different speeds. In general, there are five types of cylindrical grinding, known as outside diameter grinding, inside diameter grinding, plunge grinding, creep feed grinding, and centerless grinding.
Creep-feed grinding is a relatively recent development in grinding, having been developed in the late 1950s. This is a method for removing material at high rates of speed at depths of up to 0.25 inches. It can be nearly twice as fast as a precision grinding method. This method does have certain disadvantages, such as a constantly degrading wheel, a need for high spindle power, and a limited machining area. New advances have allowed for constant wheel sharpness and even faster grind times.
Other forms of grinding include high-efficiency deep grinding, peel grinding, ultra-high speed grinding, form grinding, internal grinding, pre-grinding, electrochemical grinding, and electrolytic in-process dressing grinding.
What do You Need to Know When Grinding Aluminum Sheet or Plate?
Aluminum poses specific problems that must be taken into consideration when grinding aluminum alloys. This is because aluminum is relatively soft and it melts easily. If you don’t know what you are doing, it’s easy for the aluminum to start melting as you grind it, coating the wheel.
As the grinding stone gets covered in small bits of aluminum, the grit of the stone is no longer exposed. The aluminum that gets caught in the wheel rubs against the aluminum being cut, increasing the heat even further and melting the metal even faster. An inexperienced grinder will push the piece against the wheel more forcefully, leading to increased friction. In the worst cases, the wheel will heat up to the point that an explosion will occur.
In order to avoid such scenarios, it’s important to use a grinder that can be dressed during the grinding process. Dressing is a technique of knocking loose the excess material from the grinding wheel, alternatively known as sharpening the wheel. If you don’t have a machine that can be dressed in process, then you would have to start and stop the grinding very frequently and dress the wheel by hand.
Your Technical Resources Partner
Grinding aluminum sheet and plate is a delicate operation and requires a certain level of expertise. Understanding the specific properties of the alloy or grade of aluminum you are working with is essential to ensure a smooth grinding process. Clinton Aluminum always has a wide variety of sheet and plate in stock in the most popular alloys.
We are committed to being more than just a materials supplier, however. Our team of experienced and dedicated technical professionals work with our customers through every step of production, from picking out the right material to using the right machining tools, to perfecting the prototyping process before going to market.
Contact us today to learn more about our aluminum sheet and plate offerings.
