How to choose 5 axis Desktop NC milling machine?

1. True 5-Axis RTCP Function

True 5-axis refers to the capability of a machine tool to achieve simultaneous interpolated motion along all five axes during the machining process, enabling cutting at any angle. “RTCP” stands for “Rotary Tool Center Point,” signifying that in 5-axis machining, the center point of the tool remains relatively stable while the workpiece undergoes cutting within the rotational motion of the tool.
The 5-axis synchronized RTCP function significantly enhances machining efficiency, reduces processing cycles, and improves machining precision. It is highly suitable for the machining of complex surfaces and irregularly shaped components.

2. Spindle performance

Spindle is the key component of CNC machine tools. During the machining process, the spindle undertakes multiple tasks such as rotating cutting tools, transmitting cutting force, cooling and chip removal.

2.1 Spindle Power
Spindle power refers to the cutting power that the CNC machine tool spindle can provide. Spindle power has an important influence on the cutting ability, cutting efficiency and workpiece processing range during machining.
2.2.Cooling System
A suitable cooling system can control the temperature of the spindle, which affects its rigidity and stability.

3. Components

3.1 Aixs of rotation
Harmonic geared motor is an advanced high-precision transmission device. With its unique working principle and excellent performance, it has attracted widespread attention in the field of precision industry. Its zero-backlash drive and compact design make it ideal for high-precision control and positioning.

Harmonic geared motorWorm gear motor
PrincipleHigh-precision harmonic transmission is realized through elastic gear transmission.Driven by the helical motion of the turbine and worm
PrecisionHigh precision, small transmission error, suitable for high precision machining and positioning.High precision, high transmission efficiency, suitable for medium and high precision requirements
LifeOften longer, high-precision gear mechanisms contribute to increased service life.It can also have a longer life, and proper maintenance can prolong the service life.
PriceHigher manufacturing cost and price.It has a good cost performance and is suitable for scenarios with medium and low precision requirements.
AdvantageHigh precision, compact design, zero backlash transmission, small return stroke error.Durability, transmission efficiency, adaptability, load change capability.

3.2  Linear axis

3.2.1  Ball screw
A ball screw is a mechanical transmission commonly used to convert rotary motion into linear motion, with both high precision and high efficiency. It consists of a threaded screw and a ball revolving chamber, the balls roll in the chamber to convert the rotational force

Ball ScrewT-shaped Screw
StructureConsisting of threaded screw and ball revolving cavity, the ball rolls in the cavityLinear movement is achieved by mating the thread with the female nut
PrecisionHigher, able to provide precise position controlUsually lower for applications that do not require high precision
EfficiencyUsually lower for applications that do not require high precisionUsually lower for applications that do not require high precision
Load High, suitable for scenarios with heavy loadslow for lighter load applications
MotionRelatively smooth, reducing vibration and shockRelatively unstable, may generate vibration and shock

3.3 Motor
Servo motors monitor and adjust position, speed, and torque in real time through a closed-loop control system for precise motion control. Servo motors are usually composed of motors, encoders, controllers, and power supplies. Their superior control performance makes them widely used in many applications that require precise positioning and high dynamic performance.

Servo MotorStepper Motor
PrincipleAdjust the control signal in real time through the feedback system to achieve precise controlEach pulse causes a certain angle of rotation
PrecisionAccuracy High precision, enabling precise position controlHigher accuracy, but possible out-of-step under load changes and high speeds
ControlClosed-loop control, real-time adjustment of motion through feedback such as encodersopen loop control
Torque It has a relatively stable torque output within the rated torque rangeTorque is steady at low speeds but decreases as speed increases
Responding High response for high-speed dynamic applicationsLess responsive, suitable for more static applications
LoadWide range of load, dynamic load adjustment capabilitySmall and medium range load
DynamicCan realize acceleration and deceleration and smooth speed change, adapt to complex motion trajectorySmall speed change, suitable for simple motion trajectory
CostTaller, suitable for high precision applicationsLower, suitable for low precision requirements

3.4 Workbench
Protection: Consider the waterproof and dustproof measures of the workbench, and choose wear-resistant or corrosion-resistant materials and coatings.
Adaptability: Consider the clamping methods of different types of workpieces to meet diverse processing needs.

3.5 Rack
Consider the structural design and material selection of the frame to ensure the stability and rigidity of the machine tool, and the key stress-bearing parts can be used.
No. 45 quenched and tempered steel, surface blackened for protection. For other parts, Al6061 aluminum alloy can be considered to reduce weight while ensuring a certain degree of rigidity.

4. Safety protection and auxiliary devices

4.1 Protective cover
The importance of machine tool protective covers is to ensure the safety of operators, prolong the life of machine tools, improve the cleanliness and comfort of the working environment, and at the same time help to improve production efficiency and processing quality.

4.2 Coolant system
Machining cutting fluids (also known as cutting coolants, cutting lubricants or cutting fluids) play an important role in the machining process, and it can have a significant impact on the cutting process and machining quality. Using the right cutting fluid can significantly improve machining quality, efficiency and operator safety.

4.3 Automatic tool changer
ATC is an important auxiliary device for CNC machine tools. Its main function is to realize automatic, fast and accurate replacement of cutting tools (cutters). ATC reduces human error, increases productivity, enhances safety and improves machining accuracy. For the Benchtop NC machining system, the setting of ATC will greatly increase the cost, volume and weight, and generally it can be ignored to ensure the cost performance of the overall equipment.

5. Machining accuracyes

Machining accuracy refers to the difference between the actual size of the workpiece after processing and the design size. The processing accuracy of the equipment can be expressed by the tolerance level.
DesktopNC five-axis machining is equivalent to IT9 level, that is, the five-axis spatial accuracy is within ±0.05mm. The general processing accuracy of traditional industrial milling is IT8, so it is already a very good indicator for tabletop NC equipment.
Machining accuracy is affected by many factors, including machine tool positioning accuracy, repeat positioning accuracy, tool quality, cutting parameters, etc.

5.1 Machining accuracy
Machining accuracy refers to the difference between the actual size of the workpiece after processing and the design size. It takes into account all possible sources of error, including factors such as the machine tool itself, tools, materials, etc.

5.2  Positioning accuracy
Positioning accuracy refers to the difference between the actual position and the expected position of each axis of the machine tool when it stops at the specified position. It reflects the positioning accuracy of the machine tool in a specific position.

5.3 Repeat positioning accuracy
Repeated positioning accuracy refers to whether the actual position of each axis of the machine tool can be kept consistent after moving to the same position multiple times. It is an index about the repeatability of the machine tool, which is related to the stability and precision stability of the machine tool.

5.4 Resolution
Resolution refers to the minimum movement distance that the machine tool control system can resolve. It is related to the control system of the machine tool and the resolution of the encoder. Higher resolution can achieve finer motion.

5.5 Spatial precision
The index control machine tool realizes the precision of movement and positioning in three-dimensional space. It involves the positioning accuracy of each axis of the machine tool, including linear axes (X, Y, Z axes) and rotary axes (A, B, C axes, for five-axis machines). Spatial precision directly affects the accuracy and quality of processed workpieces.

6. Summary

When choosing a Pocket five-axis CNC machine tool, multiple factors need to be considered, including machine tool linkage RTCP function, components, accessories, precision, price, process, etc. The following are detailed descriptions for each aspect:

6.1 Linkage RTCP function
The linkage RTCP (rotary tool center point) function is an important feature of the five-axis CNC machine tool. It allows the machine tool to keep the rotation center point of the tool unchanged during multi-axis linkage movement, thereby realizing more complex workpiece processing. Ensure that the machine tool has a reliable linkage RTCP function to meet complex process requirements.

6.2  Components
Positioning accuracy refers to the difference between the actual position and the expected position of each axis of the machine tool when it stops at the specified position. It reflects the positioning accuracy of the machine tool in a specific position.

6.3 Machining accuracy
High precision is a key requirement for five-axis CNC machine tools. When choosing a machine tool, pay attention to its positioning accuracy, repeat positioning accuracy and angular accuracy. The processing accuracy of the machine tool directly affects the quality and processing effect of the workpiece.

6.4 Accessories
When choosing a machine tool, consider its accompanying accessories, which can affect the function and scope of the machine tool. Some common accessories may include different types of fixtures, automatic tool changing systems, workpiece measuring systems, etc. Make sure that the machine tool you choose is equipped with accessories that meet your machining needs and the type of workpieces you expect.

6.5 Price
Mini Five-axis CNC machine tools are usually high-precision and high-performance equipment, so the price is relatively high. When choosing a machine tool, it is necessary to determine the appropriate price range according to the budget, and at the same time consider whether the performance and function of the machine tool can meet the processing requirements.

6.6 Process
When choosing a machine tool, you need to consider your processing technology needs. Different processes may require different types of machine tools. For example, for the processing of complex curved surface parts, machine tools with high interpolation accuracy and linkage capabilities are required. Determine your processing technology requirements in order to choose a suitable machine tool.

6.5 Technical support
Good support includes pre-sales technical consultation, after-sales service, training, etc. Make sure that the machine tool supplier provides comprehensive technical support and training to help operators skillfully use the machine tool and solve possible problems.

Taking these factors into consideration, you can search for multiple suppliers in the market and compare their machine tool models, specifications, performance and services. The best way is to contact the supplier for detailed product information and technical consultation to ensure that the machine tool you choose can best meet your processing needs. At the same time, if possible, you can also consider visiting an exhibition or field trip to understand the performance and functions of different machine tools for yourself.