This article will take an in-depth look at 5 axis CNC machining.
The article will bring more detail on topics such as:
This chapter will discuss what 5 axis CNC machining is, its construction, and how it functions.
The normal functioning of CNC machines is done along the three Z, X, and Y axes. The five axes machines have two more axes accessible, which are namely A and B. The addition of the two extra axes makes it easy to cut complex and intricate parts. The increasing usage of five axes machines is because of their capability to reduce the time of production.
The usage of a spinning cutting fitting allows the CNC machines to quickly attain the required part geometries. Since the table positions and rotates from all five axes, the stress amount on the cutting apparatuses is reduced, and that adds to the lifespan of a CNC machine. The figure below represents a five axes CNC machine.
5 Axis Machining is a type of CNC Machining. The electromechanical procedure which manipulates apparatuses around three axes to five axes, with high accuracy and precision, cutting off excess materials to create components and parts is called CNC machining. CAD creates the starting design, which is to be machined by CNC machining process. The design is now translated into several CNC codes to give programmed instructions to the apparatuses in a CNC machine.
CNC machining outputs advanced quality on turned parts using a broad range of applications that require horizontal and vertical machining.
The multitasking capability of CNC machines enables the completion of a part or component in a distinct operation with efficiency and ease. The types of applications done by CNC machines involve collars, bushings, fittings, fasteners, inserts, machined washers, machined components, pins, spacers, nuts, spindles, drive shafts, standoffs, and splined shafts just to name a few.
The setup of a 5 axis CNC machine includes:
Diamond tools usually used are high precision tools, diamond particles layer cutting surfaces. Figure 1.3 shows the machine table with a spindle utilized for carving gemstone and the motion directions of the diamond tool while machining. Even though diamond particulates are applied all over the surface of the tool, this kind of tool construction is made for cutting edges.
Depending on the cut width and the surface quality after machining, the size of the tool is selected. The diameter of the particulates coated to the tool is also in proportion to the tool head diameter. The main tool oscillates in the three axes Z, X, and Y. In this design, for the T-shape diamond apparatus as seen in Figure 1.3a, the direction of depth of cut Y-axis is the depth of cut direction. Rotation of the B and A axes affects carving curves and arcs on the object.
Substances to create jewelry are picked as sapphire, marble, and quartz which are highly brittle, the volume of the processed product is determined within 60x60x60(mm3). Due to the operation on brittle materials with high hardness, the procedure is done according to the rule of abrasive machining, so the needed rotational velocity of diamond apparatus is commonly very high, ranging from 8,000 to 12,000 RPM. Due to the distinctive shape of the diamond apparatus and the high speed of the spindle, the apparatus holder is oriented horizontally, parallel to the plane of origin (rotation). The needs for machinery design parameters are illustrated below.
| X, Y, Z linear motion Material size | 100 mm |
|---|---|
| Rotation angle of A axis | 180 degrees |
| Rotation angle of B axis | 360 degrees |
| Spindle Speed | 0 to 18 000 RPM |
| Cutting tool size | Φ(3 – 6)mm by 60mm |
| Material size | 60 by 60 by 60 cubic mm |
From the design parameters above, the main parts and components are selected first. The manufacturing of CNC machines has its basis on the primary components, present parts and systems, and then coming up with new systems according to the usage of requirements. In the design, the primary components are selected as shown below.
The machine design is inclusive of the electrical system and the mechanical system. In the mechanical system, the component assembly is required to be structured in a way to ensure stability and transmission in limitation. The machine frame attaches the shaft and the machine components to make sure there is flexible, precise, and coherent travel between the drives to produce a complete system.
The movement and spindle of axes are set in the proper directions. Inventor software is used to build, analyze and simulate the components for mechanical systems. The 3 dimensional CAD modeling of a CNC machinery is shown in the image above. In this design, Z, X, and Y axes are run by stepper motors via the ball screws. B and A axes are run from the stepper motors via timing belts. The primary design was based on parts available commercially, other parts were repurposed to meet the utilizing functions. B and A axes are calculated to guarantee strong links and bring effectiveness when the CNC machine is in working. First, it is pertinent to pick the hard machining material, the timing belt’s transmission is utilized to lower the motor’s torque, and then determine dimensions, the dynamics transmission ratio. Full CNC machine assembly is brought together using the 3 dimensional CAD simulations sketching step. Simulations of axis movement are done, resizing the components and then machining.
The electrical system is designed and installed. The power source for the motor and the controller is a DC supply with three voltage levels. Where 5VDC is utilized to give input for controllers and signals, 24VDC is utilized for the operation of stepper motors, and the power supply can be attuned in a range of 12 to 100VDC for controlling spindle speed. The electrical system of the CNC machine is illustrated in Figure 1.5 below.
In CNC machining, a component is made utilizing subtractive machining technology and cutting tools, which cuts off at the component to make the needed shape. The shape is preconfigured by the unique CAD (Computer-Aided Design) file. A program is then made in G-Code layout, which inputs instructions directly to the CNC machinery.
Presently, it is most typical for CNC Milling machinery to have only three axes to work from, Z, X and Y. Nevertheless, 5-axis CNC machinery uses more axes, to put into the cutting operation from added angles, giving bigger scope for more intricate and complicated designs. So, axes A, B, and C may be introduced.
The cutting apparatus of the 5-axis CNC Machine reaches the workpiece from one of the five axes. It moves along the Z, X, and Y linear axes and also rotates on the A, B, or C axes. Here are the corresponding axes and their motions:
These axes work along Z, X, and Y in rotational angles to bring a 5-axis cutting machine able to make complex designs while staying a really high quality to the finished component. A, B and C axis move freely to the Z, X and Y in a rotating fashion. The specific setup of the CAD design or machine determines which 2 of the 3 more rotational axes are utilized. This 5-axis setup comes at a higher cost because of the higher calibration levels and automation technology required to operate the five axis CNC machine and feed the commands.
The considerations when selecting a 5 axis CNC machining approach include:
It must be ensured that the processing power of a CNC control is great enough to calculate, control and compute the number of axes utilized at the same time.
Look ahead function for a four plus one (4+1) axes machine must be 200 blocks minimum. For more complicated 4-axis machine sequences, 400 blocks are better. For a full five axis simultaneous procedure, a faster calculation CNC control is needed. This could be a 1000 blocks voluntary look ahead function, offering extremely high calculation speeds.
Sufficient rigidity and power of the machine spindle are both pertinent factors and are at times overlooked. Nevertheless, a powerful spindle needs an even more firm mechanical design’s support. To ensure error-free and smooth cutting, the heart of the five axis CNC machining center which is the machine spindle needs to not just be adequately powerful to withstand the loads and stresses put on it but also have enough reserves to the limit. Subject to the part to be CNC machined, a not as powerful spindle of 11kW to 15Kw with a max torque of lower than 100 Nm could limit the machine’s abilities. Such machines may be affordable in the short run, in the longer view, not so much.
It must be checked that the tool holding systems utilized are either HSK or BBT to eradicate vibration. They must provide the best attachment between the tool holder and spindle under any machining conditions and at any time.
Depending on machining requirements, there could be a need to keep a constant cutting feed rate velocity or varying it for different cutting conditions. In this context, a machine which can control each situation better to improve the cutting feed rate is needed.
To make sure that the machine tool offers high degrees of durability and tolerance considerations on how it is designed and constructed are needed.
There are usually two stages here:
There are many benefits to the use of 5-axis CNC machines since they produce fewer errors and have higher productivity than traditional machining processes. As with all forms of industrial operations, inspection is a critical aspect of 5-axis CNC machining. Quality control and inspection are included in every stage of the CNC process. In addition to traditional quality control, quality assurance in regard to documentation and processes is also part of CNC inspection.
The quality inspection of 5-axis CNC machining involves three levels of inspection, which are tool accuracy, part test, and process monitoring and control.
Regardless of the accuracy and reliability of 5-axis CNC machining, inspection is necessary to ensure that the final product meets a customer’s vision and needs. Although the process is the most sophisticated production method, it still requires oversight, control, and monitoring.
As the core of any CNC machinery – especially for a 5-axis CNC machine tool – it is pertinent to monitor heat control in the frame and the spindle. Doing so does not only help prolong the lifespan of this important mechanism; it will also provide better accuracy and quality for machined parts. To avoid overheating of a spindle, it is necessary that the spindle housing and the spindle nose are cooled effectively. Heat prevention is essential during intense machining tasks, to control and reduce the heat created from the bearings and motor during higher velocities and longer machining cycles.
A built-in spindle has the motor working inside the housing of the spindle. Hence, it is necessary that the spindle housing, and the spindle nose, are successfully cooled in sections.
The main variance between the types of five axis CNC machines is where the rotational axes appear on the machine. Five axis CNC machines can either have the rotation found in motioning the table and, hence an object or in spinning the apparatus head onto a fixed material. Swivel head machinery can accommodate a heavier and larger material because it does not have to move the material at hand. In disparity, a spinning table machine can offer speed and stability for objects with less weight.
This one places a B axis, 360 degree rotary table under the workpiece. The covered machine offers a workspace fifty inches in diameter by fifty inches of height.
The ideal component of this machine is a holed cylinder, particularly angled holes. One instance is turbine housing. On a component such as this, these holes appear at different positions around the OD. In this case, a machine with this construction can set itself from one hole to the other with a motion in one axis only. Any other kind of five axis CNC machine would motion from one hole to the next on a cylindrical component using movements in two axes, or more. But on a pivoting head/rotary table machine, the apparatus only needs to be slanted one time to the accurate angle for the hole, also the spindle head must only be oriented in Z, X, and Y axes one time. Drilling an arrangement of holes then is an issue of retracting, feeding in, and indexing in B only to get to the next hole.
A more repeatable procedure is the result. More axes of positions would only add to the chances for position error to affect the motion. Another benefit of this CNC machine construction relates to material size. The fewer rotational axes motion the material, the improved the machine can facilitate large parts. This machinery does spin the material in B, so the material’s swinging is limited to this axis. Nevertheless, since this is the only material pivoting, the machine operates on tall materials effectively. Five axis CNC machines putting both pivots on the table usually are limited to materials which are small in relation to the linear movements. But this design leaves the material more fixed, enabling the machine to operate on very tall cylindrical materials.
On this CNC machine, the primary table is so big that the A-axis unit may be oriented over a broad range of positions, increasing flexibility. Efficient programming needs the programmer to precisely know where the A-axis table face locates in relation to the B pivot. This at times means the code is programmed to assume a specific position for the A axis, and leaves the operator configuring the machinery with the lengthy step of orienting the A-axis unit to precisely match this need.
An ideal component for this CNC machine is one that gives a holed ring to the spindle, mainly if that material is cylindrical and also needs to be machined around its OD.
This machine is not enclosed, so it cuts away some large parts if the axis part isn’t in place. Prepared for five axis CNC machining, it comes across more restricting limitations on material size. When the A axis part is in position, the volume of the material is limited not only with regards to the swinging about the A axis, but in accordance with how big a material it is practical to hang from the horizontal table surface.
However, the large number of XYZ movement which remains around the smaller five axis unit aids to make this type the best five axis CNC machine for usage of long extensions or tools, mainly at odd angles.
The trunnion setup may also be called a Table-Table configuration since both its rotary axes are in the trunnion table, and the head is stationary always. Most programmers and operators can easily familiarize with this configuration since it is a simple process development from standard three axis CNC machining. Since the two rotary axes are at times utilized to easily position the material; into a needed position, it is simple to picture how the machinery will behave and position during machining.
The trunnion table machine will often give better undercut abilities than other machine setups, since the table can slant farther (in one direction) than the designs of a swivel head. The trunnion setup also gives the operator a big complete practical work amount – since the table easily slants and locks in position, giving the X, Y, and Z axes their complete range of motion. In a swivel head machine construction, some of the total work envelope should be used to facilitate the tool length as the head slants back and forth. This state can be enhanced when machining with long apparatus that can affect the total work envelope extremely.
The trunnion form of the CNC machine may also be a better option for the removal of heavy metal. Since the head does not articulate, hence enabling the usage of belt driven or geared spindles, this machine kind will mostly give more torque at low RPMs. This stationary head construction also eliminates the chance of pushing a head away from orientation during machining.
This kind of machine may be either a head-head setup, where all spins are done by the head, while the table is fixed, or head-table setup which has a rotating table and a tilting head.This head-table, head-head, or construction will often enable machining of much heavier materials than the trunnion construction.
Since the table does not slant, the complete weight of the material is moved down directly through the CNC machine base and onto the ground. This makes this a very stable configuration for larger parts. Also, the construction of the table in comparison to the trunnion design enables for larger material in general regardless of weight. Also, the rotating head enables the usage of short or more average length apparatus when machining since all spins of the apparatus happen above the material.
This chapter will discuss the applications and benefits of 5 axis CNC machining.
Although five axis CNC machines were formerly only reserved for the aerospace market, they are now being used in many industries. A five axis CNC machine can be used wherever a three axis CNC machine is in there for a smoother finish and more efficiency. It offers shorter cycles and needs less manual changing of tools or repositioning. In a three axis CNC machine, the user should reposition the component being machined so the tool may reach every one of its faces. This stage may open the procedure up to alignment issues and human error. A five axis CNC machine eliminates that, offering easy access to all faces.
CAM and CAD software for five axis CNC machines may be exceptionally advanced. They offer a multitude of programming choices and at times include collision evasion and post-processors for easy connection to a machine. With the appropriate setup, these programs can even be utilized for “lights-out” CNC machining, where it is left unattended. Five axis CNC machining may be utilized for complicated 3D shapes, also for executing traditional machining on titled or odd surfaces. Some usual industries which make use of five axis CNC machining include:
Aerospace Applications: This machining giant makes the use of five axis CNC machining’s capability to make contoured edges and smooth shapes. Aerospace applications are mainly geometrically intricate and unique. The level of detail that can be achieved from a five axis CNC machine is incalculably valuable — as is its capability to make interior cuts. Another advantage to the aerospace market is that a component does not require repositioning at every pass. Using a five axis CNC machine allows it to remain as accurate as possible by finishing a component in one pass.
CNC Machining in Medical: Five axis CNC machining can give benefits to medical devices manufacturers. The high precision it gives can help the production of implants, devices and other parts in reaching demanding healthcare standards. These outputs are small, with complex detail, and a five axis CNC machine saves time and money through more efficient, accurate production and processes.
Military Uses: Parts for precise military devices are also regularly found in five axis CNC machines. Besides their aerospace applications, they can involve submarine components, compressor blades and turbines, smart weapons, sensors, high-performance engine parts, stealth applications, and even nuclear weapons. While not all of them are military applications, nearly half of all five axis CNC machine buyers buy them for projects or contracts with the American government.
Energy Equipment: A five axis CNC machine can make specific and detailed parts that energy equipment needs. When operating on particularly resistant, rough materials, using a five axis CNC machine may offer stability to a work area, making it easier to shape and cut. It can also make the procedure more efficient, lessening the wear on tools.
Other industries which make use of five axis CNC machining include pharmaceuticals and food processing.
Five axis CNC machining aids in the affordable manufacture of sophisticated designs. The benefits of switching to five axis CNC machining include:
A five axis CNC machine allows the working of every surface, beside the bottom and the clamping area. When operating on contoured components or components that need machining on numerous faces, there is need several for setups of the three axis CNC machine to obtain the complex geometries through manual rotations but five axis CNC technology finishes the task in a one setup, lowering the amount of setups and helps with saving time.
The additional motions available with five axis CNC machining enables the achievement of complex designs and shapes. With the five axis CNC machine, there is the ability to machine arcs and angles which were formerly attainable only through manifold setups and numerous special fixtures. Ultimately, five axis CNC machining gets rid of the need to make complex fixtures as the part is held once and rotated in a single procedure to attain the desired geometry.
Every time a component is removed from a machine, the precise alignment that enables superior quality achievement is lost. Unlike three axis CNC machining, five axis CNC machining enhances accuracy by enabling the completion of a job in one set up, and produces multiple and complicated shapes without loss of the precision needed to maintain quality.
In five axis CNC machining, the cutting apparatus stays at a tangent to the cutting surface, enabling low cycling time spans, which helps reduce as more material is removed every time the apparatus passes.
The fifth and fourth axes help with orientation and bring the component closer to the cutting apparatus, allowing the use of a shorter cutting apparatus, which is less vulnerable to vibrations at exceedingly high cutting speeds. This helps achieve an improved surface finish. It also saves time which is not the case when utilizing a three axis CNC machine. Use of really small cuts must be made to attain a better surface finish, longer lead times are then imminent.
The drawbacks of 5 axis CNC machining include:
An initially higher investment is often required for a 5-axis CNC machine and the necessary software. The total investment cost is often higher than the total cost of a standard 3-axis machining center. Moreover, the maintenance needed is at times more complex.
There are two more rotational movements involved in addition to the three linear movements, making 5-axis CNC machining more complicated than 3-axis CNC machining. Consideration is also required on the coordination of the movement of each of the axes, to evade collision, interference, and the suitable interpolation motion amount. To optimize the needed surface quality and machining precision, complex programming could be a challenge, which could need the services of a qualified programmer.
5-axis CNC machining is a cutting-edge technology where the setup, programming and machine process need higher skilled technicians.
From the points above, it is clear that the advantages of using a 5-axis CNC machine likely outweigh the drawbacks. However, the variety of challenges imposed when choosing a 5-axis CNC machine should still be considered.
Travels and Capacity
CNC Machining Spindle
Tool changer
Feed rates
5 Axis Size
5 Axis CNC Machining Electrical
Some considerations when maintaining 5 axis CNC machines include:
The major benefit of 5-axis machining is the ability to produce intricate and complex parts due to its adeptness. This aspect of the process decreases production time from start to completion. The avoidance of crashing by revolving the cutting tool or work table offers a rapid and efficient approach to various part geometries and avoids the need for reprogramming or extra machining.
The normal machine centers of CNC machining are built around the 3-axis model, which are the X, Y, and Z axes at the center of the machine. The 5-axis configuration adds two machining centers to increase the motion of tools.
Included in 5-axis machines are five axis forms, which are:
Double Swivel Head Form - With the double swivel head form, two rotation coordinates control the direction of the cutter axis directly.
Droop Swivel Head Form - The droop swivel head form has the two coordinate axes at the top of the cutter with the rotational axis not perpendicular to the linear axis.
Double Swivel Table Form - In the double swivel table form, the two rotation coordinates control the space rotation, directly.
Droop Table Form - With the droop table form, the two axes are on the table, while the axis of rotation is not perpendicular to the axis.
One Swing, One Rotate Form - The one swing, one rotate form has two rotation coordinates with one on the cutter and one on the workpiece.
A 5-Axis CNC machine offers industries the chance to undertake jobs that they were formerly unable to complete. For manufacturers who presently use 3-Axis CNC machining, the advancement to a 4+1 or even full 5-axis CNC machine is the next logical step in their investment and production planning. Due to the price of such machines, nevertheless, it is advised that customers fully understand which procedures best meet the specific production requirements. There is also a need to pick the right CNC machine tool to realize the profitability and efficiency of production completely.
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