Reaming is an essential operation in part manufacturing. You use it to expand a previously drilled hole in metal workpieces. It involves utilizing high-precision rotary cutting tools to remove material from a hole and refine it. This leaves a hole with the desired roundness and surface finish.
However, reaming is not crucial for all applications. It adds to the overall machining time and should only be used when important. This article explains what reaming is, when you should use this process during product development, and tips to follow for the best reaming experience.
What Is Reaming?
Reaming is a machining process that aims to enlarge the size of an existing hole. With reaming, you do not have to drill a hole. The operation helps to refine the hole to achieve dimensional accuracy and make the part suitable for various applications. To carry out this process, you use a tool called a reamer. Reamers are rotary cutting tools that are cylindrical. They come in different designs that affect how and where you use them. You use them manually or with CNC machining to create holes with smooth finishing. The most common types of reamers are taper pin, shell, floating, and straight flute.
Taper Pin Reamers: The distinguishing feature of this reamer type is the gradual taper from the tip to the body. Taper pin reamers convert straight holes to ones used for taper pins.
Shell Reamers: Shell reamers are cylindrical tools with a hollow body and multiple flutes around them. You use them with a mandrel or arbor during a reaming operation.
Floating Reamers: They are specialized types of reamers that come with spiral flutes. You attach a floating reamer to a holder, which is mounted on a CNC machine. They remove excess material to refine an existing hole.
Straight Flute Reamers: Straight flute reamers are general-purpose reamers used for blind and through holes. They have multiple straight-cutting edges along the shaft.
When Should Reaming Be Used in Machining?
The reaming process comes immediately after drilling. It involves clamping the workpiece and choosing a reamer with the correct design and size. You then mount the reamer and align it with the hole. After that, modify the reaming parameters and execute the operation.
There are many instances when reaming is desirable in machining. Some of them include
- You should ream a hole when the parts come with strict tolerance requirements. Basic drilling and boring operations cannot achieve tolerances as tight as +/- 0.005mm. Reaming ensures components fit accurately and precisely during assembly.
- Reaming should be used when superior surface finish is desirable. The process cleans all forms of flaws and imperfections. This is important in areas where you want to reduce friction and premature wear.
- Furthermore, reaming helps to achieve uniform hole diameters along the entire length. With this, inserted components fit perfectly and won’t fall off.
- You can also use reaming to slightly enlarge an existing hole. You control the amount of material removed per rotation. Enlarging existing holes is desirable to avoid over-drilling and prevent tool breakage.
- Additionally, you do not only use reaming for initial machining operations. This process also has applications in repair and maintenance work. Reaming helps to repair damaged holes and prolong the lifespan of mechanical components.
Tips to Optimize Reaming Processes
The process of reaming is easy to carry out, even for novices. However, there are some considerations you should keep in mind for the best results. The following are some tips you can employ to optimize a reaming operation.
Ensure Proper Setup and Alignment
Proper setup and alignment are essential to avoid errors. This involves mounting the reamer holder on the machine spindle correctly to prevent deflection. You should also position the workpieces well and use appropriate work-holding jigs and fixtures. Consider using a reamer holder to ensure proper orientation when working when blind and very deep holes.
Select the Right Reamer
The cutting tool you use makes all the difference during a reaming operation. Based on your project requirements and what you aim to achieve, select the correct reamer. Ensure the reamer is compatible with the workpiece material for proper hole refinement. When working with metals that are hard and difficult to machine, consider using spiral flute reamers. Conversely, straight flute reamers are best for materials not prone to chipping.
Optimize Reaming Parameters
When reaming a hole, make sure you use the correct parameters, such as spindle speed, feed rate, and depth of cut. The speed at which the reamer moves should be relatively slow to prevent overheating and damage to the tool. Based on the material properties, you should modify the depth of cut and feed rate. Generally, use a shallow depth of cut and low feed rate when reaming to ensure even hole diameter.
Prioritize Cutting Fluids
Cutting fluids such as lubricants and coolants benefit reaming in many ways. These fluids help to manage the heat generated when reamers are in contact with the workpiece. Additionally, they aid in chip removal and prevent clogging. There are different types of cutting fluids you can use. They can be oil or water-based. Your choice depends on the metal in question and the desired surface finish.
Optimize Hole Preparation
Another tip for a successful reaming operation is proper hole preparation. When drilling the hole, ensure it is straight and near perfect to make reaming easier. For the best reaming experience, the pre-drilled hole should be slightly smaller than the final reamed size. This will accommodate for the material you would remove during reaming.
Conclusion
Reaming is an operation carried out after drilling a hole using different types of reamers. While it is a critical step in many manufacturing processes, there are instances where you do not need to ream a hole. It is crucial to carry out the reaming process when high dimensional accuracy and tight tolerance are required. Additionally, this operation is essential to achieve uniform hole diameters with a superior surface finish.