Manufacturing most parts requires drilling holes in the workpiece. Although the process may seem simple, it requires the right method, tools or exercises to achieve excellent results. The methods and tools used to drill metal and plastic differ based on the material properties.
In this article, we will discuss how to drill a hole in metals and plastics and what tools are needed to make the perfect hole. We also show you different drills and bits that you can use for drilling.
How do you drill holes in metal?
There are several reasons why engineers and craftsmen drill holes in metals. The reasons can be structural, functional, aesthetic or one of the post-milling processes. Regardless of the reason or purpose of the hole, here's how to drill a hole in metal.
Get the Right Drills and Bits for Metalworking
The drill has an adjustable table under a motorized spindle. It also has a chuck for lowering the rotating drill bit into the metal. To control the depth of the hole being drilled, the operator raises or lowers the drill table or sets a depth stop.
Depending on the thickness of the metal, two main types of drill bits are used to drill holes in metal. The first is the sheet metal drill bit. This drill is ideal for drilling thin metals, as it cuts the metal in a way that prevents it from cracking. The other is the high-speed twist drill, ideal for thicker metals. This drill has a shank and groove that move chips out of the hole.
Mark the hole in the metal
It's best to mark the hole to make sure you're drilling the correct area of the metal. You can do this by using a marker and ruler to draw short lines that intersect in the center of the hole. It is best to make a small dent at the marked center point with a center punch to prevent the drill bit from slipping while drilling.
Adjusting the speed
Whether drilling holes, grinding or other CNC processes, speed plays an important role in determining accuracy. You can adjust or change the drilling speed by opening the drill belt guard and unscrewing the knob on the motor housing to release tension built up in the pulleys. You can then slide the motor frame forward to make it easier to slide the belt from one plane to another.
Note that lower speeds correspond to the lower pulleys, while higher speeds are achieved by wrapping the belt around the higher pulleys.
Drilling the hole
To start drilling, insert the drill bit into the drilling chuck and tighten it. Then clamp the metal part onto the machine table or in a vice. Rotate the bit and drill while applying even pressure.
Keep your workpiece free from dirt by removing splinters and splinters while drilling. Add cutting fluid as you work to reduce friction and allow for a smooth cut. After drilling, remove the bit from the hole and turn off the power.
Tips for drilling a hole in metal
Drilling holes in metal with a drill can be risky. For example, a workpiece clamped too loosely may get stuck and thrown away by the rotating drill. To avoid accidents when using the drill, it is best not to hold the piece with your hands while drilling. Instead, use at least two C-clamps to secure the workpiece to the table.
Also, do not wear gloves when using the drill, as loose parts of the glove may get caught in the drill. Also wear safety glasses to protect your eyes from splinters and splinters.
How do you drill holes in plastic?
Unlike drilling metal, drilling incorrect holes in plastic will result in cracking and chipping. These defects can affect both the aesthetics and functionality of the part or product. To avoid this, see how to make a hole in the plastic correctly.
Prepare tools
The tools you need to drill successfully include a pencil, ruler, tweezers, tape, twist drill, sandpaper, and lubricant.
Mark the drilling location
Using a ruler and pencil, mark the places on the plastic where you want to drill. This marking helps to avoid possible drilling errors.
Protect plastic
Use a clamp to secure the plastic to a sturdy surface large enough for the area of plastic you want to drill. The procedure for securing plastic when drilling a hole is similar to that used for drilling and helps reduce the tendency for resistance to impede drilling.
Make sure you have the correct drill size and use
After attaching the plastic, the next step is to make sure you have the correct size drill bit. After confirming the drill size, insert the drill bit into the drill bit and tighten it. Then move the drill forward.
Start with the slowest drilling speed
If your drill has an adjustment dial, choose the lowest drill speed. If this is not the case, place the drill bit lightly on the plastic before drilling. When drilling, always pay attention to the consistency of the resulting chips. If you notice that the chips are starting to stick together, it is best to stop drilling at this point to allow them to cool.
Tips for drilling holes in plastic
Drilling holes in plastic is not an easy task. Therefore, you need to follow basic tips to do everything right. Here are some tips for drilling a hole in plastic.
- Do not continually puncture the plastic. Instead, stop frequently to avoid overheating, which can melt the plastic.
- Start drilling into the plastic at low speed and increase speed as drilling progresses.
- To avoid accidents, always use a clamp to hold the plastic part in place.
- After drilling, make sure the chips are removed from the plastic part.
Various drilling machines to make a hole
Drills are available in different versions, each developed for a specific purpose. Here are some of the common machine types.
1. Radial Arm CNC Drilling Machine
In this drill, the spindle is mounted on a rotating arm. This arm rotates around the column and allows radial movement of the spindle, feed mechanism and drill head. An advantage of this machine is that it allows drilling in several locations without changing the position of the part.
2. Multi-spindle drill
This machine drills multiple holes in a single part simultaneously, using the same pattern for each section. It is ideal for producing similar parts in large quantities.
3. Line punching machine
A multi-spindle drill consists of several independent columns, each mounted on a common base and equipped with its own motor and spindle. These tools are generally used when performing several consecutive operations, such as: B. drilling and threading must be carried out.
4. Tower drill
A rotating turret is the centerpiece of a turret drill. This machine is typically ideal for mass production drilling jobs that require multiple holes of different sizes and depths to be drilled in a single part. With a revolver drill, only one hole is drilled at a time.
5. Micro drill
This small drill uses manually controlled power to make extremely precise microscopic holes. These machines are used in industries such as electronics or jewelry making that require small, precise holes.
6. Vertical CNC Drilling Machine
This machine has an electrical feed mechanism that drives the tool into the workpiece without human intervention. Furthermore, vertical drills are ideal for heavy-duty applications due to their robust construction.
7 types of hole tools
1. Drill
These tools make drilling cheap and easy. Drills work by axially penetrating the workpiece before cutting a blind through hole. There are different types of drills that are ideal for you in different industries.
Common drill bits include twist drills, center drills, tap drills, point drills, masonry drills, and step drills.
2. Reamers
Reamers are often used after drilling to obtain holes with the most accurate hole diameter possible. The most commonly used reamer is the chuck reamer. There are also Morse taper reamers, automotive reamers, welding machine reamers, taper pin reamers, and toolmaker reamers.
3. Hole Cutter
Hole cutters, also known as hole saws, are necessary for making precise round holes in metal, wood, and other materials. These tools can cut much larger diameters than a typical drill bit. They are also a very effective replacement for other tools because they only need to cut the perimeter of the hole. Hole cutters have separate cutting teeth with carbide tips, just like circular saw blades.
4. Countersinks and chamfer bits
Drills with chamfers and countersinks are ideal for making conical holes in objects. Additionally, a countersink drill expands an existing hole with a tapered opening at the top when it penetrates axially into a workpiece. These commercially available drilling devices ensure that fasteners fit snugly into the workpiece.
Countersink and chamfer bits are available in various sizes and shapes to suit drilling needs and preferences. Angles such as 60°, 82°, 90°, 100°, 118° and 120° are typical countersunk angles.
5. Center drill
Center drills have a pilot drill and a countersink. They are typically used to create a center hole in a workpiece that facilitates turning between centers and supports the load during turning. These drilling tools are advantageous due to their extreme rigidity and low tendency to wobble. Furthermore, the average hole angle of a center drill is 60°.
6. Brooches
This is a multi-tooth tool for drilling holes. Due to its length, the brooch is ideal for deeper cuts. Broaching is an important phase of drilling, as it facilitates the production of parts with an incredible surface finish. The most common types of this tool include cup, keyway, push and pull, outer surface, and inner broaching needles.
7. Countersink bit
Countersinking, typically performed after drilling, is perfect for applications where a fastener must be perpendicular to the surface of the workpiece. Typically, these countersinking tools have two different cutting diameters: one for the hole and one for the recess in the head.
Considerations and tips for drilling holes
As with CNC engraving or other CNC machining processes, there are some challenges when drilling holes, especially deep holes. Here are some tips to keep in mind when drilling holes.
Choose the right CNC drilling head
There are numerous drill bits that differ in their construction, design, and intended use. Choosing the right CNC drill head can be difficult and is a common cause of many drilling problems. By checking compatibility, you can be sure you are using the correct drill head. It would be best to discuss the ideal strategy with a drilling expert or service provider.
Chip removal and breaking
Whether you are drilling holes in metal or plastic, be sure to remove chips during and after the drilling process. Controlling them is crucial as they can lead to several problems.
One way to control chip formation is to use a special chip breaker to split the chips so they can be removed more easily and a chip breaker inserted. Furthermore, chip crushing improves drilling performance and heat dissipation. Use intermittent feeding while increasing feeding.
Feeds and speeds
The type and shape of the material determines the feed rate and drilling speed you would use for the process. In general, to drill a pilot hole (maximum ½ inch in diameter) in rigid plastic, a feed rate of 0.005 to 0.015 inch per revolution and 600 to 1000 rpm is recommended. However, metals tolerate high feed rates, while drilling plastics at high speeds can result in chipping and cracking.
Choose Wayken for your drilling projects
Concluding
Drilling is an important aspect of manufacturing products and parts because it creates holes for assembly and connection. Although the drilling process seems relatively simple, it is generally not necessary as technical knowledge is required to carry it out professionally.
Common questions
What is the CNC code for drilling a hole?
There are three main CNC codes for drilling holes: G81, G82 and G83. G81 is the most common cycle. An example of typical G81 queues are .
How deep can a CNC drill?
Never drill more than 12 times the nearest drill diameter. Drills this long or longer lose rigidity and the ability to maintain tight tolerances and are more likely to break. If you need to dig deeper, consider increasing the diameter of the hole.
Which tool is best for drilling holes?
To make precise round holes in metal, wood and plastic, you should choose hole cutters, also known as hole saws. This metalworking tool can cut much larger diameters than a typical drill bit.
