Technology

How to improve slip ring quality

1.The detection of dynamic contact resistance
slip ringTo be bested for slip ring mounted on 360-degree turntable rotation detection by motor driven turntable, so that a continuous conductive slip ring rotation in the detection process, the dynamic contact resistance of each loop is a dynamic display whichever is the maximum and minimum, in order to ensure the stability of the loop conductive transfer, the loop of contact resistance variation of no more than 9m.

2.Insulation resistance testing:
To prevent the loop between the insulation resistance should be not less than 500M, MOFLON produced the electrical slip ring is a multi-channel precision positioning ring group ring, vacuum pressure casting epoxy formulation materials, precision machining, after heat curing made.

3.The slip ring life testing:
rotary slip ring is used in point-contact throughout the manufacturing process to ensure that the brushes and ring groove wear life, MOFLON purchased Chinas first slip ring tester, according to the different use of the environment (high temperature, voltage, speed, frequency, data rate), can be test to life for electrical slip ring in different environments. Each batch of material produced will have a strict life test for 15pcs/5set sample in 21 days in advance, then make sure the production of wear life and quality .
After learn about the slip ring manufacturer process to grasp the importance of points and made the manufacturing process some of the key parameters required, MOFLON as the countrys first specialized in electrical slip ring manufacturers, and have enough design experience , manufacturing experience, also collected and accumulated many goods suggestion from customers to fill the gaps in the field. In order to best service for our customers, we are very pleasured to work with global partners in the field to carry out more extensive cooperation, achievement partner, client-side products to achieve greater value creation .Monofilament precious metal electric brush improved the shortcomings of the composite metal electric brush, small debris, small volume, the stability of the signal transmission is good, but the carrying capacity is very limited. Fiber brush electric brush`s design uses a plurality of metal fibers, and to maintain a multi-point contact with the metal ring body, and having excellent electrical conductivity and high current density. And the environmental sensitive requirements in the fan cabin are much lower than other several types of contact.

Generally speaking, low-cost slip rings are using the plastic housing mostly, demanding slip ring using a metal housing.

MOFLON slip ring, except the capsule slip ring, the others are the metal housing , under normal environments, the slip ring using aluminum alloy housing , corrosive environments using stainless steel material.

The most important of the electrical slip ring is contact, first electrical slip ring in the structural design to ensure the reliability of the contact, to ensure that all of the line is turned on continuously, the electrical slip ring assembly by several important parts of the slip ring body, the noble metal contact point component, fixed bracket, the common core ball bearings, etc. The design and manufacturing process of large parts will affect the wear life of the slip ring, the slip ring mandrel electrical ring material is usually copper, brass, coin silver or gold materials, in the electrical ring surface need to plate multilayer precious metal substances act to reduce the impedance of the metal body in an instant rapid conduction extend wear life of the slip ring and reduce electrical noise. To ensure the sufficient contact between the brush and the electrical slip rings, electrical slip ring and is designed into a V shaped annular groove of the slip ring contact, in order to pass the signal and the current conduction, thus requiring brush used the materials has very good electrical properties, the pressure of elastic pressure on the slip ring should be appropriate, reduce the slip ring eccentric and shaking deviation, good abrasion resistance, friction torque is small, easy to maintain. Also consider shielding, impedance matching, noise voltage, etc.

electrical slip ring as a kind of precision machinery parts, level of technology directly determines the product quality is good or bad, experienced designers will take advantage of some of the common processing defects principle to make up the design, during engineering design, often encounter is how to connect with a functioning part, the electrical slip rings biggest role is to ensure the connectivity of the equipment in the free rotation, usually including the transmission of power, signals. Therefore, the characteristics of the preliminary manufacturing process is to make full use of 3D modeling tools and simulation tools, process full storm drain and displayed so as to grasp the level of good process design, to lay the foundation for all aspects of the behind process.

The slip rings is a precision part, every process has strict working requirements, and working personnel’s working attitude for the quality of the product plays a crucial impact. Such as: the quality of the insulating material may cause leakage and so on.
Material requirements are fairly strict, the insulation properties and pressure resistance of insulating materials. The selection of contact materials, must have good electrical properties, but also wear-resistant, corrosion-resistant. There are some equipment in the outdoor, considerable temperature difference within one year, minus 30-40 degrees in the winter in some places, summer working environment temperature reaches 70-80 degrees, so we should take full account of these factors when material selection and testing.
Within a small volume slip ring connected voltage sometimes thousands of volts, current of several hundred amperes, there are a variety of complex signals simultaneously over a few hundred lines, how insulation between each passage, how the signal lines not to interfere with each other, is definitely not an easy thing to do, this is the designers need to carefully consider.

Dynamic resistance of the slip ring is the dynamic contact resistance between the electric brush and ring body can be measured by Micro ohm Micro voltmeter table. It is normally a fluctuation value, mainly due to the defective on the surface of the metal ring of the slip ring or between the ring and the brush has the foreign body, the pressure is not enough, virtual contact causes, etc. Because the surface treatment can not be absolutely smooth, Precision Slip ring products are cutting-edge military technology was only in recent years, everyone is familiar with the major industry has been widely used. As every industry use of slip ring in different environments, different type of signals, then there are not uniform with important performance parameters for production of the structure size, performance and life requirements. But the slip rings have main performance parameter will influence the production of stability, reliability, and life. This article summarizes the factory of actual production which use Slip ring of the import parameters for working process, and have general summary of key points.so the fluctuations value of the slip ring`s dynamic contact resistance can not be eliminated, generally requires that can not exceed 10 milliohms, minimum can be reached 1 milliohm. The fluctuations value of slip ring`s dynamic resistance will affect the slip ring`s signal transmission accuracy, so when purchasing the raw materials is necessary to strictly control the plating treatment of the metal ring surface, in production must carry strict requirements on the contact surface cleaning and the pressures of electric brush and metal slip ring. The pressure of the contact surface of the conductive ring should be controlled between 10-15 GF.

First, the structural safety of Slip ring design:
Electrical Slip ring are made up slip ring body, brush assembly, the combination of frame, concentric precision ball bearings. It adopt to multi-channel precision positioning Ring Ring module, vacuum pressure casting ring in the ring epoxy resin formulations at a high temperature curing material after the precision machining. pancake slip ring is a double brush II design , with the highest quality of gold alloy slip ring as the ring groove and the corresponding body symmetric double contacts, use of the electrical brush of flexibility pressure sliding contact with the ring groove to pass signals and current, thus ensuring the adequacy of exposure and durability.
Engineers must be considered to users many factors when design the production, example: mechanical installation, performance requirements, reliability, product life speed, current, voltage, temperature, vibration, protection degree and signal type when design the production, and also important to focus on the slip foolproof ring product manufacturing reliability.

Second, the manufacturing process.
As per above mentioned, the capsule slip ring is a double-brush II design with the highest quality of gold alloys as a slip ring body, and the corresponding symmetric double-ring groove contact position, using the brush pressure of flexibility and V ring groove sliding to contact, then transmit signals and current. in the manufacturing process have following three points must be strictly controlled. 1. Adjust the wire brush contact with the ring groove is best to make a good wire brush on the pressure in the ring groove, and will not affect the rotation, if adjust pressure is too small will result can not be contact. the pressure is not enough, or too much pressure will increase the friction torque, make contact position have a large wear, it made shorten the life for slip ring. 2. Workshop environment to shorten the life reach a certain leval of cleanliness will result in a dirt ring groove surface adsorption can also cause false contact or resistance value in creases. 3. Ring groove in the pre-production process can not be subject to external quality materials to withstand external shocks or gravity will be deformed, Shenzhen MOFLON material used in the process of working iron box filled with packing foam cushioning the impact of cotton to control the external gravity . 4. It is very important to choose the material, it must be have good thermal conductivity, high melting point (temperature) , high conductivity, temperature coefficient of resistance is small, fast signal transmission frequency bandwidth also need to have anti-curing materials, antioxidants, anti-corrosive gases, high temperature super-wear and other physical characteristics, can not just use low-cost materials or do not have the above characteristics of slip ring life will be greatly reduced, MOFLON uses of expensive gold alloy to ensure high-quality long life slip ring products.
Third, the slip ring performance parameter testing.

Parameters of the slip ring detection can be reflect the overall performance of slip ring connector and solution the some problem immediately. test parameters, including the appearance of the product structure inspection, slip ring normal life testing, static contact resistance, the dynamic contact resistance, insulation resistance, electric strength and the friction torque detection, here introduced the electrical slip ring normal wear life of insulation resistance, the dynamic contact resistance were detected and analyzed.

A designer can be expressed as one image by computer simulation publication. The modeling is usually the first step, a rapid prototyping technology system. Mechanical drawing of the construction work of any kind of economic accurate time and information, skilled in the art may have found a better way to local, to correct these problems may require modifications by modifying the original design or damage to the local. Drawings of this type are also used to the planed new process.

Processing, the details of the production processes determine the quality of the slip ring, in the slip ring production processes, preliminary design drawings, planning, should to pay particular attention to detail and craftsmanship key points.

To control the production quality of the slip ring, the first is to avoid errors in the design, occurred addition to usually work carefully, while two or more audit engineering drawings can also minimize the occurrence of errors. During the production, each product should firstly tested by the quality department personnel before bulk production, for item numbers, size, material, installation process , assembly of each slip ring component requiring must be strictly in accordance with the requirements on the engineering drawings. The bearing quality problems within the electrical slip ring may result in rotation were.

The design engineer may need to introduce value-added design to the existing local, but the factories may be reluctant to release its internal computer-aided design files for proprietary reasons. At the beginning of this task, the mechanical 3D slip ring product model more effective in assistance of communicating ideas design. In the production process, the control of the size must be strictly in accordance with the engineering drawings request processing, for the engineering drawings, it is necessary to go through the recognition of two designers before entering the production chain, each procedure should be completed to the next step after checking engineering drawings.

For process control and grasp need the human factor, and team co-ordination. Slip ring as a kind of precision parts, The production process requirements are particularly strict, especially high number of rings, multi-channel, small size, miniature slip ring, due to the small size of this kind of slip ring, and the spacing between channels is not large, moreover, the internal structure is very sophisticated, a little small error could lead to the entire parts scrapped in the normal production process, staff training runs through the entire production process, the most important thing is not enterprise assets, is the people, products quality needs to be guaranteed by the people. Between the people and companies need to establish a relationship of mutual trust, it is the only way to achieve the best interests of the employees, by the way to achieve the company’s goals and ideals. For the software facilities, training of staff is on the one hand, working hours try not to be too long, realize shift system, the best working time of a team is not more than eight hours, one-time continuous working time is preferably not more than a 1-hour, then 15-minute break. Work and rest to play to their enthusiasm and maximum efficiency, product quality can be best protected, to give up or to gain, there are only can give up firstly, and then can gain.

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