The Best Choice: A Box Way CNC Lathe

Posted on Nov 3, 2020

Box Way CNC Lathe

The four main considerations when choosing a CNC box-type lathe are speed, rigidity, load capacity, and tool life. The box-type CNC lathe is stiff and has a slightly slower feed, but can make heavy cuts on large parts.

This is different from machines built with linear guides. They can move at high feed rates and are suitable for light workpiece applications. The deciding factor when choosing a made-to-measure CNC lathe is what is the application?

In this case, linear ways provide a reduced coefficient of friction and heightened feed, acceleration, and braking speeds. Some machine builders like this because they can utilize faster speeds and very high feeds. But over time, the benefits of higher feeds comes at the expense of dynamic stiffness.

This affects the accuracy of the detail under dynamic machining conditions. Also during short-axis movements, as in a CNC lathe, the travel path is insufficient to achieve these speeds, and therefore rapids become negligible.

A CNC box-type lathe can be designed with a variety of box styles, such as metal or metal, to Turcite ©, or metal with a wide range of advanced polymers. Although machines with a CNC lathe with a box slide are not able to move at the feeds and speeds of linear guides, they have the significant advantage of greater dynamic stiffness.

A CNC box lathe requires the perfect art of hand scraping to achieve the required geometric specifications. This happens when a craftsman scrapes the metal with a scraper that has a carbide tip all over the surface. Repetitive exercise of rubbing the slider to recreate the way the profile forms the points of contact, or "bearing".

Care was taken to evenly distribute the carrying points. The surfacet is made after the scraping process is complete and creates a crescent-shaped appearance that provides proper oil distribution channels. The laborious and tedious attention requires craftsman and their skills are improved and some are even certified.

:: Read more : About Linear Guides Installation


Linear Guide versus Box Way CNC Lathes

Linear guides are more prone to failure in the event of machine failure. Subsurface cracks can occur in the balls or rollers of the system and eventually cause the system to fail. A CNC lathe with a box, on the other hand, tends to suffer less damage due to the large contact surfaces. Box guides provide a great advantage over linear guides in terms of stiffness and load.

In addition, a CNC box way lathe has a much better vibration damping ability than linear guides. They can even be used in very difficult machining applications such as the hard milling of pre-hardened steels and high nickel refractory aviation alloys.

Another advantage of rigid chassis machines is that they extend the life of today's carbide and ceramic tools by damping vibrations that can damage tooling. The box way CNC lathe allows customers to slide the partial load envelope by simply reducing the fast pace.

Consequently, a CNC box way lathe is always preferred when the application requires a rigid machine with a high weight capacity. And if they are need a longer tool life, and superior damping from vibration, then box way CNC lathes are the choice. Only they possess this ability to machine hard materials.

Some companies use box guides with non-metal inserts running on removable hardened guides to dampen tool-induced vibration. According to the machine tool builder, this type of system withstands high spindle thrust loads and enables the company's horizontal production centers to make 50hp cuts on parts weighing up to 40 tons.


Single Rail Systems

The monorail linear guide system has integrated trolley bodies with plastic recirculation lanes that are injection molded directly into them. These tracks reduce the number of components and ball recirculation passes for quiet ball operation, ensuring high precision and speed. The wagons run on a rail with a trapezoidal profile, which optimizes the cross-section of the bogie for stiffness.

Today, most people working with machine tools know the difference between box and line systems. And let's face it, when box roads are mentioned, large machine tools come to mind. Most think of huge machines that are stiff, a bit slower, taking deep cuts on large parts. Linear guides, on the other hand, suggest faster and lighter machines. However, no matter what the system is, the problems are the same, speed, stiffness, and load.

Are engineers trying to determine what loads the machine will have to support? And what load damping do you need? And finally, how many traverses will there be? Some companies believe that linear methods may be more susceptible to failure in the event of machine failure. Cracks can occur in the system's balls or rollers and eventually cause it to fail. Box ways are usually less prone to damage because of their large contact surfaces. But once the box system is damaged, it becomes more difficult to repair.

:: Read more : A CNC lathe machine might be the only machine you need!


Benefits of Box Way CNC Lathes

Box way versus Linear guides require less surface preparation for assembly compared to precision grinding of the top plate and the bottom of the box way. On the other hand, strong friction bearing systems such as box guides can have a blocking/slippage problem that affects circular interpolation. To make a circle, the axis of the machine moves in one direction slows down and moves in the opposite direction.

There is a speed zero point during this change of direction. The box arrangement produces the difference between the static and dynamic coefficient of friction. This can be seen in the ballbar test and perhaps with the loss of machining precision.

Some believe that wear occurs every time a plain (box) bearing moves. Machine performance fluctuates and becomes less accurate over time. In the case of rolling bearings (linear guides), the wear is much lower. In fact, says Schuler, rolling bearing manufacturers can actually determine how long a bearing will last without significant wear.

The guides of linear systems are relatively small compared to the large areas of the guides and their sliding elements. Minimal contact significantly reduces friction for better response and faster high-speed travel speeds. Speed ​​is, of course, a key factor in choosing a guide. Therefore, many designers have worked to improve speed in both box and line systems. Instead of Turcite, they use Rulon, more dense material with minimal stickiness/slip, as a mating surface with the box.

In regards to eliminating and reducing the surface drag, some machinists like to add lubricating oil. They usually choose a high viscosity oil that is at least half the thickness previously used. This pressure-dosed impulse lubricant film runs along its entire length and is only pumped during rapid feed movements.

Acceleration to the maximum traverse is almost instantaneous, stick/skid is practically non-existent, and distortion-inducing heat dissipates quickly, which increases efficiency. This makes the CNC box lathe one of the most sought-after equipments for the production of high-quality turned parts. 


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