Finishing operations are critical to the quality and functionality of machined components. Flaring as one of the finishing processes ensures that the holes in your part have the best diameter accuracy, dimensional tolerance and best surface finish. Manufacturers usually use it after the drilling processes are completed.
What is rubbing? What are your purposes? How can you get the most out of the rubbing process? This article answers these questions and discusses the CNC reaming process in detail, including the issues involved and tips for getting the best result.
What is enlargement?
Flaring is a cutting process that increases the diameters of existing holes more accurately and improves the surface finish of the hole walls. The flaring tool used for the flaring process is called a “reamer”. This operation is a finishing operation and does not cut much material compared to drilling or drilling. Furthermore, the reamer rotates at exactly half the speed of the drilling process when machining the part.
What is the purpose of widening?
The main purpose of reaming holes in a part is to improve its dimensional accuracy, surface quality and tolerance level. Manufacturers choose machining with a reamer as it is the best option due to its speed and low cost. CNC reaming can provide better surface finish with its precision grinding capabilities and create holes with specific sizes and diameters.
Processes such as drilling and boring occur before metal reaming because they need to prepare the hole before reaming. A hole reamer is the ideal choice when you need to maintain tighter tolerances, exactly -/+ 0.002 inches or more in hole diameter.
How to Ream a Hole: A Step-by-Step Guide
To achieve optimal results with this precision machining, you must prepare your holes with the correct amount of material for reamer cutting. If the material is too small, the reamer will ream the hole, leaving a smaller diameter than necessary. However, if there is too much material, the hole may become too large and have a rough surface finish.
Here are some steps to widening a hole:
Step 1 : Make sure the workpiece is securely in place and secure it with clamps to prevent it from slipping or wobbling. Enlarge the hole with the correct reamer. Typically, the reamer is 1.5 times larger than the hole.
Step 2 : Identify and drill the hole in the workpiece using a spot drill bit with a slightly larger taper than the drill bit used to drill the existing hole. However, to obtain the desired results, do not drill with a pilot drill.
Step 3 : A good rule of thumb for determining the ideal drill bit size is to subtract 2% – 4% from the reamer size – minus 2% for harder metals and 4% for softer materials.
Step 4 : Use the correct feed and speed for the material, reaming tool and operation. However, make sure the bit and hole are well lubricated with coolant or cutting oil during CNC reaming operations.
Step 5 : Control the advance and speed of the reamer
- Rotations per movement (RPM): Use 1/2 – 2/3 of the speed used when drilling the hole;
- Feed: Use twice the feed of the drill used
Step 6 : Sand the top of the hole with a 90º or 82º countersink to break the edge.
Step 7 : Use lighter cutting oil or coolant for lubrication because reaming operations do not necessarily require heavy cutting fluids for high performance. It allows you to obtain a precise size and a smooth surface for the hole walls.
Passi 8 : Avoid stopping the reamer during operation or poking the walls of the hole with the reamer until it exits the bottom of the hole. With the machine turned off and the spindle stopped running, pull the reamer straight out of the drilled hole.
Different types of reamers
Common reamer types include the following:
1. Manual reamer
Manual reamers are categorized as rose or slot reamers, which have a small cone on the cutting end to facilitate insertion of the reamer. These reamers can be solid or extendable. However, its expansion is limited to a certain extent. Additionally, the manual reamer has blades arranged irregularly around its body to minimize the possibility of shaking.
2. Floating reamers
These reamers can be used to correct misalignments between the already drilled hole and the axis of the reaming tool. Pendulum reamers have two interchangeable and changeable cutting edges that are held together in a groove in the reamer and can be moved in the radial direction. These reamers are particularly suitable for rotating parts on turret lathes.
3. Accessory reamers
Reamers are used with reamer mandrels, which ensure an ideal fit of the hole in the reamer. These reamers are specifically designed to clear material and produce well-finished holes milled to the desired size.
They are used in screw machines, drills, automatic screwdrivers, lathes, etc. Groove reamers are an economical option for your large hole reaming needs.
4. Carbide reamers
Carbide reamers are ideal for machining areas with high abrasion resistance. They offer longer useful life and excellent surface finish of the hole. Carbide reamers create a perfect hole around your shaft instead of wasting time on the previously drilled hole.
Common problems with friction
Several complications arise when trying to ream a hole in a workpiece. That includes:
1. The reamer creates hopper openings that are too small or holes that are too large due to misalignment and incorrect feed and speed.
2. The reamer may jam and break due to large surface roughness, unsuitable tool material or insufficient cutting fluid supply to the cutting area.
3. The reamer may degrade the surface finish of the hole due to uneven chamfers, vibration, excessive spindle runout, or improper cutting action.
4. Excessive tool wear or breakage occurs due to misalignment or extreme friction pressure.
Tips and Precautions for Friction Operations
For the operation to be successful, you must follow some useful tips and precautions when scrubbing. Here are some of them:
1. Reamer feeds and speeds
Feeds and speeds for reamer machining can vary significantly depending on the material that needs to be CNC milled, the type of machine, and the surface finish and precision required. In general, mechanical reaming is most often performed at about two-thirds the feeds and speeds used for drilling holes in the same material.
The feed rate in metal reaming is generally higher than that in drilling, generally being 200 to 300% of the drilling feed rate. Too low a feed rate can result in excessive reamer wear. Therefore, the feed must be high enough so that the reamer tool can always cut and not rub or flatten.
2. Alignment
Perfect alignment of the spindle, bushing, reamer and hole to be milled is crucial to the reaming process. The spiral angle also needs to be adjusted appropriately to be consistent with the other parameters. Any deviation will likely result in increased reamer wear and compromised hole accuracy.
For oversized, conical or funnel-shaped holes, it is necessary to check the alignment of these parameters. Sometimes errors due to misalignment can be minimized by using adjustable supports.
3. Re-sharpen the reamer
One of the principles of cutting tools is to ensure that the tool does not become too dull before replacing or sharpening it. It would be helpful to resharpen the bevel on a reamer before it wears out or stops cutting.
However, sharpening is limited to the chamfer or entry cone only. You must be very careful to sharpen each groove evenly, otherwise the tool will be too large. It is not advisable to sharpen the bevel manually as it is difficult to maintain consistent cutting edges.
4. Focus on stock levels
The material tolerance for reamer machining is 0.010″ for a ¼” hole, 0.015″ for a ½” hole, and up to 0.025″ for a 1½” hole. In manual reaming, on the other hand, the addition of material is much less because it is more difficult to push the reamer through huge material. Therefore, the standard tolerance for a manual reamer is 0.001 to 0.003 inches.
5. Avoid conversations
Shaking during reaming operations damages the hole surface and the reamer working on it. Shaking can be caused by lack of rigidity in the machine, excessive distance in the reamer, excessive reamer swing and insufficient feed. To minimize or eliminate vibrations during a reaming operation, reduce the cutting speed and increase the feed.
How do you determine the size of a latch hole?
Reaming is an efficient and faster method of completing a hole compared to methods such as drilling. However, when reaming a hole, the size of the hole must be taken into consideration. If you make the hole too big, it will be difficult for the reamer to do its job. Likewise, if you make the hole too small, it won't work. For best results, you must drill the hole to be milled to the correct size.
As a general rule, leave 0.010 to 0.015 inches of material remaining after the drilling process for the reamer to scrape off. For small diameters, such as 1/32 inch or less, there should be 0.003 to 0.006 inch of material remaining that can be removed by CNC reaming.
However, it would be better to use a percentage instead of a fixed range. It would help if you made the hole diameter 2% to 3% smaller than the reamer. You can change the hole diameter to be 5% smaller than the reamer diameter if conditions are favorable.
Enlargement vs. drilling: What are the differences?
Reaming, boring and drilling processes are different machining operations that help create a new hole or modify an existing hole in a workpiece using various cutting tools. However, to understand the differences between enlargement and enlargement and enlargement and enlargement, we must consider these processes in isolation.
To scrub
As mentioned previously, CNC reaming is a cutting process that uses a rotary cutter to create holes with smooth interior walls in a part or to modify existing holes. However, reaming requires an existing hole prepared by the drilling process.
The rotary cutter used in reaming operations is commonly called a reamer and removes significantly less material from a part than bits used in drilling operations.
The main function of the reamer/grater process is to provide smooth walls to existing holes. Manufacturers perform reaming operations using a drill or milling machine. The size tolerance when rubbing metal is approximately IT9⁓IT6, while the surface roughness value Ra can reach 3.2⁓0.2 µm.
Tedious
It is a cutting operation that uses a single-end milling cutter or drill bit to expand an existing hole in a workpiece. The drilling process is completely different from drilling, which involves making a new or first hole in a workpiece.
You can drill a hole using a milling machine, lathe or horizontal drill. Although drilling creates an initial hole in the workpiece, the drilling process helps to enlarge the resulting holes. The hole diameter is not limited by the tool size. The drilling machining process has significant error correction ability and high positioning accuracy.
Multiple cutting can correct deviation errors from the original hole axis, and the drilling process can produce different holes with different sizes and precision. The drilling accuracy is IT9⁓IT7, while the surface roughness is between Ra 3.2⁓0.8 µm.
Stick
CNC drilling is a typical process that uses a drill to make circular holes in workpieces. A machinist must press the drill bit against the workpiece to make a hole. The drill drills into the workpiece and creates a circular hole when the drill is activated.
Drilling creates the conditions for the formation of a threaded hole. This allows a standard hole to be drilled in harder materials, such as metal, in preparation for subsequent hole machining. Therefore, the drilling accuracy is lower than that of boring and reaming, only IT13⁓IT11, while a high surface roughness of Ra 50⁓12.5µm is achieved.
In summary, the main difference between these three methods is clear. Reaming creates a thin inner wall inside the existing holes, boring increases the diameter while drilling creates the hole in the workpiece.
When is enlargement preferable?
Reaming and drilling are ideal finishing techniques that can create holes with precise diameters and tighter tolerances. However, there are certain factors that may necessitate the decision to ream rather than drill. Here are some of them:
1. Grating saves time
A reamer is a multi-bladed cutting tool with up to 10 teeth, depending on size. It reduces cycle time and its many teeth provide much faster feed speeds, increasing productivity compared to machining a single tooth. Therefore, CNC reaming is a better option than drilling when time is a factor.
2. Simple process
Reaming is the best option for a hassle-free drilling process. It is easy to adjust the reamer for heavy-duty reaming operations. The flaring tool does not need to be constantly adjusted in diameter as the tool has a correct preset diameter. The reaming process is more stable and safer than single-point drilling, which requires constant adjustments.
3. Better quality
Reaming offers better quality than boring due to the multiple cutting edges. With a reamer you can achieve the tightest tolerances at higher speeds and feed rates. The reamer's multiple cutting tools not only save time, but also produce the highest quality parts.
Get perfect hole machining service
With more than 20 years of experience in machining, we can machine all types of holes, such as: B. by reaming, drilling, boring or threading. You can be assured of a high quality machined part.
Concluding
Flaring is one of the standard finishing techniques best suited for finishing holes in your workpiece. It is a practical and economical machining method for smaller holes. However, to obtain the best result in your reaming operations, you must pay more attention to using the correct reamers with the correct helix angle.
Common questions
What are the uses for scrubbing?
Reaming is commonly used to remove burrs and basically enlarge holes while achieving a high-quality surface with precise dimensions.
What does the reamer do?
Reamer vibration may be due to lack of rigidity in the machine or bushing. Furthermore, it can be caused by very light feeds, unstable fixation of the part or excessive protrusion of the reamer.
What are the benefits of scrubbing?
The advantages of reaming include faster feed speed and greater drilling accuracy. Likewise, high-speed reaming helps improve hole machining and gives the hole a better surface finish.
