CNC boring and CNC drilling are both important machining processes. They allow you to make holes in a number of materials. But these two methods are vastly different in their tooling, purpose as well as benefits. In this blog post you will learn about the main differences, applications and benefits of CNC boring and CNC drilling.
What is CNC Boring?
CNC boring is the process of enlarging and refining existing holes using computer controlled machining. This process uses rotating cutting tools such as boring bars to adjust hole diameter, geometry and surface finish. CNC boring can get very tight tolerances usually within ±0.0005 inches. Industries like aerospace and automotive manufacturing use CNC boring for their precision‐driven components.
Also See: A Complete Guide to Boring Machining
What is CNC Drilling?
CNC drilling is a computer controlled machining mechanism which produces round holes by rotating a drill bit and pushing it into a stationary workpiece. Unlike manual drilling, CNC drilling is automated so it’s faster, more accurate as well as consistent. You can use CNC drilling on plastics, metals and composite materials. It’s great at creating holes for aesthetic or assembly purposes.
Main Differences in CNC Boring and CNC Drilling
1. Purpose and Functionality
Boring: CNC boring enlarges or improves holes which already exist. A boring bar with a single cutting point rotates within a hole to control the surface finish and diameter. Although CNC boring is slower, it’s necessary when your project needs very precise hole dimensions.
Drilling: In contrast, the purpose of using CNC drilling is to get new holes. A rotating drill‐bit moves into the material to form cylindrical holes. Because of its speed and proficiency, CNC drilling is great for tasks such as making fastening points or pilot holes.
2. Tooling Requirements
Boring: CNC boring uses single point cutting tools on boring bars. These tools encourage precise adjustment of hole diameter and mostly have specialized coatings for machining harder materials. Compared to drill bits, boring tools are more customized and expensive.
Drilling: CNC drilling, on the other hand, uses drill bits with multiple cutting points. These drill bits come in different materials and sizes like high speed steel and carbide. Purpose‐built drill bits such as micro drills or deep hole drills may be needed for your project. Generally drill bits are simpler and cheaper than boring tools.
See Also: 10 Types of CNC Machine Tools
3. Tolerance and Precision
Boring: CNC boring is more precise with tolerances of ±0.025 mm or better. It gives smoother hole surfaces and extraordinary cylindricity. If you need very tight tolerances then you should use CNC boring.
Drilling: As opposed to CNC boring, CNC drilling is moderately precise with tolerances of ±0.1 mm. It is usually good enough for standard applications. But if you need higher precision, you’ll need additional finishing steps.
4. Materials and Compatibility
Boring: CNC boring is good for finishing holes on tough materials like titanium alloys and hardened steel. Its precision and ability to machine harder materials make it a preferred method in automotive and aerospace industries.
Drilling: You can also use CNC drilling on multiple materials like steel, aluminum, composites and plastics. But drilling has trouble with very hard materials such as titanium alloys because these materials not only generate a lot of heat during machining but they also wear out the tool very quickly.
5. Machining Proficiency and Time
Boring: CNC boring is slower than drilling. It’s all about precision. A single point cutting tool separates material gradually and this assures precise dimensions and outstanding surface finish. Though boring takes longer times, it’s necessary for applications which need tight tolerances.
Drilling: In comparison with CNC boring, CNC drilling removes material fast. It uses drill bits designed to cut fast into the material which shortens cycle times. It is good when you need to produce large quantities of holes quickly.
6. Axial Length Adjustment
Boring: CNC boring has more flexibility for axial length adjustment. You can extend or retract boring bars to get accurate hole depths. This flexibility makes it best for complicated or deep holes particularly in high risk parts such as engine blocks.
Drilling: In contrast, axial length adjustment in CNC drilling is limited. Max hole depth depends on spindle travel of your machine & length of drill bit. To drill deeper holes you need to use special long drill bits. However these longer bits can increase tool wear and reduce machining stability as well.
7. Cutting Action
Boring: CNC boring enlarges an existing hole using a radial cutting method. A boring bar with a single point cutting tool gradually removes material from inside of the hole. This controlled process not only supports precise‐diameter adjustments but gives better surface finish too.
Drilling: In CNC drilling, on the other hand, a multi point drill bit cuts along the axis of the hole. As the bit enters the workpiece, the cutting edges form a cone at the bottom of the hole and remove chips through the drill’s flutes.
8. Financial Impact
Boring: CNC boring is more expensive because of slower machining and customized tooling. Boring bars and titanium nitride coatings add to the upfront cost. Moreover setup and skilled operators also add to labor cost.
Drilling: For simple hole making, CNC drilling is more cost‐saving. Less expensive tooling and faster cycle times mean lower net cost.
9. Tool Rating Speed
Boring: CNC boring tools run at lower speeds compared to drilling usually between 500 to 2,000 RPM. Slower speeds give you more control over hole enlargement. This minimizes tool wear and gives outstanding surface finish.
Drilling: In comparison with CNC boring, drill bits used in CNC drilling run at high speeds – 1,000 to 5,000 RPM as per material type. These high speeds remove material fast. However higher speeds can also increase tool wear when machining harder materials.
10. Hole Shape Control
Boring: CNC boring has extraordinary hole shape control. You can precisely adjust the radial position of the single point cutting tool. This lets you make complex hole shapes like stepped, tapered and concentric holes. Thus boring is best for modern engineering applications which need custom hole features.
Drilling: When you use CNC drilling, the drill tip forms cylindrical holes which end in a cone. This works well for simple hole designs. However if you need complicated shapes such as stepped or tapered holes then drilling alone cannot get these features. Additional machining steps are needed to get more complex hole geometries.
11. CAD/CAM Programming
Boring: Programming CNC boring is more complicated. You have to use more advanced G code like G85 or G86 to define hole dimensions. Boring‐specific CAM software mostly has advanced features such as detailed cutting parameters and optimized toolpaths. These help you get more accuracy and proficiency particularly in high precision machining.
Drilling: Programming CNC drilling is straight‐forward. You use basic G code such as G81 to define hole depths, positions as well as feed rates.
See Also: What is Computer Aided Manufacturing (CAD)
12. Surface Finish
Boring: CNC boring produces a better surface finish. Single point cutting tool gives you more control over the cutting action. So you get a smoother surface with fewer irregularities and mostly no need for secondary finishing.
Drilling: Multi point drill bits in CNC drilling run fast and give a rougher surface finish. You may need additional operations such as polishing or reaming to get a smooth surface.
CNC Boring vs CNC Drilling Benefits
CNC Boring Benefits
| Benefit | Details |
|---|---|
| Accurate | CNC boring is accurate. It assures holes are in alignment & of accurate size. |
| Finishing critical parts | It’s best for finishing precision‐driven parts like molds or engine cylinders where dimensional accuracy is most important. |
| Tight Tolerances | Operators can control hole dimensions during CNC boring. So results are consistent even in large quantities. |
CNC Drilling Benefits
| Benefit | Details |
|---|---|
| Fast | CNC drilling machines are fast. They can run at high speeds and are much faster than manual drilling. |
| Easy Setup | Operators can quickly set up CNC drilling machines because of intuitive programming interfaces. |
| Affordable | CNC drilling is cheaper in large volume manufacturing because automation reduces labor cost and material waste. |
Applications in Different Industries
CNC Boring
| Industry | Application Details |
|---|---|
| Engine‐Cylinder Resizing | CNC boring is used for engine cylinder resizing. It corrects wear and tear, restores original cylinder shape and can increase engine displacement. |
| Aerospace | CNC boring is utilized a lot in aerospace component manufacturing. Landing gear assemblies, engine casings and structural rings are some examples. |
| Mold Manufacturing | CNC boring refines holes in mold bases for injection and cooling systems. It improves mold quality for different processes such as plastic‐injection molding. |
| Heavy Equipment | CNC boring is used for large diameter parts. These may be flywheels, gearboxes or turbine housings. |
CNC Drilling
| Industry | Application |
|---|---|
| Automotive | CNC drilling creates accurate holes in transmission parts, engine parts & vehicle chassis. |
| Electronics | Electronic parts, printed circuit boards, electronic enclosures and control panels all use CNC drilling. |
| Aerospace | CNC drilling is used for turbine parts, hydraulic assemblies and fuselage sections. |
| Construction | Construction components like structural parts in heavy machinery frames, booms and axles in cranes and excavators use CNC drilling a lot. |
Selection between CNC Boring and CNC Drilling
Choose between CNC boring and CNC drilling based on your machining objectives and precision needs. If accuracy is necessary then CNC boring is a better choice. It refines existing holes to precise measurements and gives a high finish. Automotive and aerospace mostly use CNC boring for this reason. But if speed is more important compared to extreme accuracy, CNC drilling is better. It forms new holes quickly and is good for general purpose tasks like inserting fasteners or drilling pilot holes.
To Sum Up
After knowing the difference between CNC boring and CNC drilling we can conclude that both have their own advantages. CNC boring is more precise and accurate whereas CNC drilling is fast and affordable.
If you need any kind of CNC machining services – boring, drilling or any other – then Richconn is your best option. You can contact us anytime.
Related Questions
Can CNC boring tools do internal threading?
Yes internal threading can be done with customized boring bars which use combined multi operation boring bars or threading inserts.
How does tool wear in CNC boring differ from CNC drilling?
CNC boring tools have single point cutters which wear slower and more gradual. In contrast tool wear occurs faster in drilling because of multi point cutting action and high speeds.
What tolerances can CNC boring achieve?
Depending on machining conditions and materials, CNC boring can get tolerances of ±0.005 to ±0.001 inches.
Can CNC boring and drilling be done in one automated cycle?
Yes advanced CNC systems like FICEP’s Excalibur can automate boring, drilling and other machining work in one CNC cycle.
What are basic errors in CNC boring and how to avoid them?
Incorrect tool alignment, vibration issues and programming errors are basic CNC boring mistakes. Avoid these by selecting the right tool, calibrating equipment as well as optimizing cutting parameters.
How do feed rates and spindle speeds differ between CNC boring and CNC drilling?
CNC boring has slower feeds and lower spindle speeds to give better surface quality & precision. On the other hand CNC drilling has faster feeds and higher spindle speeds to be proficient.
What is the importance of coolant in CNC boring?
Coolant helps to dissipate heat, remove chips and minimize friction. This gives the best surface finish quality and increases tool life in CNC boring.
Are bore‐drill combination tools appropriate for high volume production?
Yes. Combination of bore‐drill tools work well for high volume production as it not only minimizes tool changes but reduces cycle times too.
