Molding machine is a kind of high-performance forging equipment that can cut and plasticize the coil, and can produce hundreds of bolts per minute. According to the different structure of forging die, can produce a variety of parts and screw blanks. This paper describes the structure and characteristics of the equipment, which is indispensable in the process of bolt making, and introduces the latest function and development trend of the molding machine. In recent years, in the molding process worthy of special attention to the two aspects of technology: First, replace the preparation process and improve the operating rate of technology; Second, high-precision molding technology.
1. The production of bolt blank
Bolts are mainly made of top upsetting machine or bolt Roll Forming Machines. The nut blank is mainly made of nut Roll Forming Machines. Simple shape of the bolt blank through the two processes upsetting can be processed, hexagonal bolts and hex bolts through the 3-4 process upsetting can be processed. The production of nut blanks was mainly cut prior to the 1950s and is now available in 4 to 5 steps upsetting.
2. Molding machine
The molding machine is a kind of horizontal press, which is mainly driven by crank mechanism. The molding machine cut the incoming material, i.e., the coil or bar, into a predetermined length, and then the blank was sandwiched between a fixed forging die (female mold) and a moving die (male mold) for molding. It is mainly used for bolts, rivets and parts of the cold upsetting and hot upsetting.
3. The construction of the molding machine
The molding machine is composed of a transmission device, a feeding device, a shearing device, a forging device, a pushing device, and a handling device.
The main transmission device to the main generator, the power transmission to the transmission mechanism. It is regularly driven by pneumatic clutch gears and cams.
The feeding device is composed of a straightening machine, a conveying roller and a feeding driving device. The feeding machine is used to straighten the curved coil material; the conveying roller is used for feeding the wire into the roll; the feeding driving device is used for adjusting the conveying stroke of the wire, and the conveying length of the wire reaches the prescribed requirement by the transmission drive.
The shearing device is a device that cuts the wire into a prescribed length. It is provided with a stopper for controlling the conveyed material to stop at a prescribed position; and a push-out machine for pushing the cut wire from the shearing machine.
The forging device turns the rotary motion into a reciprocating motion through the crankshaft, thereby driving the plunger holding the male mold.
The push-out device is composed of a KO on a female mold side on which a molded blank is pushed out from a forging die and a PKO on a male mold side.
The handling device is a device for conveying the blank to the next process. The nut Roll Forming Machines is equipped with a rotating chuck capable of reversing the molding direction of the male mold and the female mold by 180 °. In addition, the bolt Roll Forming Machines is equipped with an open cam and a timing switch to hold the manipulator.
The drive system of the molding machine drives the entire system with a main generator. Each organization can work according to the set time.
Roll Forming Machines processing procedures are:
1) After straightening by the straightening roller, the material end of the material fed by the feed roller stops when it stops against the stopper and is then cut to a predetermined length by a shearing machine. The cut blank is then conveyed to The position of the push machine;
2) in the push-up position, the blank is pushed out of the shearing machine by the putter, and then pushed out with the conveying robot in the first step;
3) The blank conveyed to the first female mold position by the transfer device can be molded into the female mold by the first male mold, molded and pushed out from the female mold, and then pushed out by the second transfer robot;
4) The subsequent process repeats the operation of the three steps described above, and the predetermined shape is formed in the final step.
The advantages of the molding machine are as follows:
1) equipped with cutting device inside, in order to facilitate the transport of blanks, from the material to the final process can be continuous automatic production;
2) production speed, each minute to produce hundreds of pieces;
3) because it is continuous automated production, so the impact of human factors, processing accuracy deviation is small.
4. Molding method
4.1 Positive extrusion method
Positive extrusion method is to put the blank into the mold, so that the material along the forward direction of the forward movement, the production of radial or cup-like extrusion method. Reducing processing is divided into free-to-restraints on the outer diameter and closed compression of the outer diameter.
4.2 Reverse extrusion method
Reverse extrusion method is to put the blank into the mold, with a male mold to squeeze, so that the material in the male and female mold gap or the empty part of the male mold to move, the production of cup or shaft products extrusion The
4.3 Upsetting method
The upsetting method is the method of extruding the billet in the axial direction and extending the material in the radial direction. It can be divided into the blank diameter of the unconsolidated upsetting method and in the forging die will be the outer diameter of the (semi) closed upsetting method.
4.4 Shear processing
Shear processing is to clip the material between the two tools, the use of different tools for cutting the cutting process. The blank is cut to a predetermined length on the molding machine, and then the blank is punched into a cup shape, and then the hollow molding punching is carried out. Finally, the outer diameter of the blank is punched and trimmed.
5. The latest developments in equipment
In recent years, Japan has turned to the production of special shapes and high value-added large parts. In production is worthy of special attention to the following two points, one is to replace the preparation process and improve the operating rate of technology; Second, high-precision molding technology. The following is a brief introduction to its latest developments and their device functions.
5.1 Replacement preparation process and improve job rate technology
1) Straightening machine with double-headed drawing
In the production of large-scale, long-size products, about 30% of the use of wire production. Therefore, the replacement of wire varieties of high frequency, timely supply is very important. The straightening machine with double-headed wire drawing is different from the straightening machine used in the production. It is a straightening machine parallel to a straightening machine. It is used as a stand-by machine. It can be used to load the wire during molding. The bending portion is straightened, and the wire for supplying the molding machine is prepared in advance. When the wire in the production run out, as long as the next production line with the straightening machine to replace, you can complete the wire replacement preparation process, greatly reducing the replacement time.
2) The overall replacement system for the forging device
The overall replacement system of the forging device uses a hydraulic cylinder to hold the female mold and the male mold for holding the forging die. Therefore, when the preparation process is replaced, the button can be used for switching operation. Since it is possible to replace the forging device as a whole, it is possible to shorten the replacement preparation time by using the vehicle in the workshop, the equipment driving, or the robot.
3) Lifting mechanism of female mold device
Large die for the mold device is generally more than two. In order to lift the mold in the forging machine, due to fear of the mold will be rack scratches, so the lifting operation of the mold should be careful, and the operation is difficult. The use of female mold lifting device, you can make the lifting operation of the mold becomes simple, it can use the hydraulic cylinder can be down to a certain position of the mold device.
4) automatic adjustment of the position of the front and back of the male mold
The machining temperature of the forging die varies with the change of the processing time, which may lead to the change of the product size. In order to correct this change, the effective way is to set the electric automatic adjustment device of the front and rear position of the male mold.
In the past, this correction operation requires the suspension of the molding machine, and then by the operator into the machine to adjust the position of the male mold. As a result of the development of automatic adjustment device, it can be adjusted during the operation of the equipment, but also can solve the early operation of the equipment on the impact of changes in product size, effectively improve productivity and reduce the incidence of adverse products.
5) Transfer the rack and pull out the inner core
When the transfer rack is raised from the operating position, the transfer device is aligned with the operator due to the transfer to the operator's side, so it facilitates the replacement of the manipulator and the pull-out adjustment of the core while ensuring that the inside of the forging device There is a lot of space, so as to improve the operability.