Universal turning machines are relatively small in size equipment mainly for the processing of piece blanks. In simple models, spindle and axis drives do not require complex automation to control, everything is simplified to the maximum. Often a digital display device is used in the design to control the position of the axes.
Separate equipment class
Universal turning machines acquire small production sites, repair shops, amateurs. The processing process can be visualized, as well as implement automatic control using a conventional low-power computer. Finalization instructions can be found on the Internet, all information is open.
Most often they purchase small universal lathes, the price of which starts from 1 million rubles, from Russian and Chinese manufacturers. If you take European equipment, then the cost may already be about 10 million rubles, depending on the size and configuration. In Russia, customers give preference to brands of Taiwanese machine tool builders, who have an almost perfect price-quality ratio.
Universal lathes for work are close to complex machining centers, where the processing process is fully automatic. But setting up a cycle without CNC is not possible without using a computer. However, when the cost of modern CNC is comparable to half the cost of the machine, control from an old PC will be much more cost-effective. The necessary software is in the public domain, and working with it does not require additional investments, except for the costs of studying manuals.
Universal turning machines have high geometric accuracy. They can be installed on the foundation without anchoring. Modern electronics make it possible to realize micro-feed for the axes, which expands the possibilities of processing parts.
What can be produced?
The widespread use of machines is due to their versatility, namely the ability to process various surfaces with a minimum changeover time of equipment. An experienced craftsman is able to turn a part according to a drawing with laboratory accuracy.
The types of processing on a universal turning and milling machine are as follows:
- External turning, boring, end face machining.
- Universal lathes allow machining parts by cutting. The technology is implemented thanks to the axial rotation of the workpiece and the translational movement of the tool.
- Drilling If there is a spindle positioning function and a milling head, then the machine is capable of producing parts with holes in any position of the workpiece.
- Milling of helical surfaces (in the presence of a dividing head and a rotary table). Threading external and internal.
- Processing by cold deformation during rotation.
Design
A turret with a 12-position driven tool greatly expands the capabilities of the equipment. The tool disk is performed at the request of the customer for a larger number of positions, but at the same time the cost of equipment increases. A turntable is an option, available for order only with more expensive models.
To process the rods, a bar feeder (barfeeder) can be connected to the machines. The bar is automatically fed through the spindle of the lathe directly to the clamping device. To implement the technology, you will need a hollow spindle with the required bore and adapter sleeves for each diameter of the workpiece (so that there is no bar chatter during rotation). Also, the machine must have a compatible interface for electrical connections.
The dividing head is a cheaper counterpart to spindle positioning. To implement the latter option, expensive CNC boards are required. The head is easily mounted to perform one-time milling tasks at various angles (for example, to obtain hexagonal surfaces).
Compactness
A universal lathe with a DRO has a minimum of electrical parts, which are correctly packed in a bed or in a separate wall cabinet. Effectively used workspace, where it fits easily: a small turret, tailstock and spindle chuck. Axes have coordinate limitations by software and emergency limit switches.
The compact location of the working nodes allows the use of machines in the medical industry (dentistry). All mechanical components are standardized. You can re-adjust the equipment for any production task. On many models, a milling spindle (milling head) can easily be installed at the cartridge mounting location. Or instead of the tailstock, mount the counter spindle.
Spindle
In all lathes, the main unit is spindle. According to its power, the supply power is calculated. It can be hollow or simple depending on the production tasks.
In universal machines, a manual gearbox (which is a set of gears with shift levers) is more often used.
The gearbox allows you to change:
- Part speed (revolutions).
- The force of rotation is the moment.
The main geometric parameter of the spindle is runout, which on modern equipment is not more than 5 microns. For axial positioning of the spindle, an encoder (angle sensor) is used, as well as an electronic board responsible for tracking the position sensor. The main motor can be asynchronous or synchronous execution.
Powerful spindles are equipped with a cooling system. If the latter is available, continuous processing of parts at maximum speeds is allowed.
Key Features for Choosing Equipment
Before searching for a machine, you must have the technology requirements. They are guided by the following criteria in the process of searching for equipment:
- Dimensions - the distance between the centers (clamping length of the workpiece), the height from the bed plane to the axis of rotation of the spindle (center height), the diameter of the spindle bore, the lateral movement of the workpiece and the stroke length of the tailstock (pintles).
- The mass retention of the workpiece.
- The spindle torque is taken into account.
- Axial force.
- Clamping pressure of spindle, counter spindle, tailstock.
- The mass of the machine.
- Maximum spindle speeds.
- Types of spindle cones, tailstock. Dimensions and type of tool to be installed.
Feedback from users of equipment
Repair shops, almost all production facilities, furniture factories, even private traders prefer to purchase universal turning machines. The price of the simplest professional models starts from several hundred thousand rubles. Less functional units can be purchased and cheaper, but this is not recommended due to the use of poor quality materials.
When using universal screw-cutting lathes, productivity is increased at least 2 times. And with such a cost of equipment, its purchase is the most profitable acquisition.
What experienced users think about machines:
- For example, workers speak of Proma SPE-1000PV 25971000 quite positively as the most simple and successful model of a universal metal lathe. Many say that this is a simpler model than the Proma SPF-1000P 25100000, but its functionality is not inferior. All the gears are metallic inside and the "big brother" also, only the manufacturer regretted the oil, I had to add that it was really called an oil bath. They also add that the quality is comparable to Soviet machines.
- In the model of the classic machine "Red Proletarian 1K62" users highlight the reliability, safety and ease of use for many years of operation. Particularly pleased with the versatility of the work performed, reliability, quality of manufacture and assembly, the unit is suitable for individual production like no other.
- On the budget model of the machine JET GHB-1340A worth 400 thousand rubles, users leave somewhat ambiguous reviews. Many write that maximum savings on everything, extreme processing options on the verge of a foul. If it is used in a repair shop, then there is enough for the little things of the machine. For production, users are not advised. The unit is made for 4+ - casting defects are visible in some places, but this does not affect the work. Lightweight, so reviews do not recommend handling heavy workpieces. The diameter of the treatment and the length are quite suitable for everyone.
Recently, the most popular universal CNC lathe. Software control extends processing capabilities to the maximum. The production process becomes fully automated. For the implementation of the technology, it is no longer necessary to train personnel for many years, just one experienced installer in a huge fleet of equipment is enough.
Commissioning works
Despite the simplicity of the models, universal lathes are sophisticated devices. Trained people should manage and commission them. Despite the apparent simplicity of equipment installation, each master has to deal with non-standard tasks.
Commissioning includes 3 stages: foundation production according to the manufacturer’s drawings, adjustment and commissioning of geometric accuracy. The standard thickness of a monolithic foundation for a bed weight of more than 1 ton is 300 mm. Only under such conditions it is possible to set the level of the machine and give a guarantee for work more than 1 year.
Geometry options
The accuracy of the machine is checked by the following parameters:
- End and axial runout for spindle.
- Level.
- The longitudinal movement of the axes to the spindle.
- Transverse axes to the spindle.
- Spindle alignment with tailstock or counter spindle.
- Beating cone of the tailstock.
- The position of the boring holder to the axis of the spindle (in the presence of a turret).
The accuracy of the machine is set by the manufacturer, the master after installation, and is also monitored periodically by maintenance personnel.