Zhi Dan Zheng

Influence of Dresser Setting and Assembling Errors on Shape Precision of Form Wheel

Influence of dresser setting highness error and assembling error on size precision and shape precision of dressed wheel section is studied and error emulational analyzing is carried out in NC dressing form wheel. Analyzing results indicate: influence of dresser setting highness error is quite small and can be ignored, influence of dresser radial or axial assembling error on shape precision of dressed wheel section is biggish and influence of axial assembling error is bigger among them, the latter can bring wheel section shape error of the same order as itself. Therefore, necessary measures must be taken to insure that assembling errors is smaller than 10 μm in dresser assembling, then requirement of form wheel dressing precision can be met.

Error Estimate of Approximate Double Circular Arc Interpolated Method for Curve Smoothing

Approximate Double Circular Arc Interpolated Method which was put forward by author, is different from other circular arc interpolated methods in demanding only the corner between normal directions of each circular arcs at intersection point are less than designated allowed value but not demanding contiguous circular arcs are tangent, and makes the calculating be predigested. In order to estimate error of the method, emulated calculating is carried out, namely the course of curve being obtained by reverse engineering is simulated in this paper. The results show: if space between measure points is about 0.1mm in curve being obtained by reverse engineering, then, the most departure of smoothing results from original curve is 0.552μm for the stated example. Influence of the error on NC machining is quite small, so it can meet the needs of NC machining.

Discussion on Electromagnetic Radiation Protection Standard of Light Industrial Equipments

The popular international and Chinese electromagnetic radiation protection standards are introduced, including the ICNIRP guidelines constituted by the International Commission on Non-Ionizing Radiation Protection, the EN62233 standards established by the European Committee for Electrotechnical Standardization and the GB 8702-88 regulations constituted by Ministry of Environmental Protection of the People’s Republic of China, etc. The situation of the light industrial equipments electromagnetic radiation has been tested and analyzed: the power of the induction heater is often up to thousands kilowatts, and there are many electrical control components and many dense circuitries in light industrial equipments. Their complicated electromagnetic fields release continuously electromagnetic waves and engender electromagnetic radiations to the surrounding environment. And, Chinese electromagnetic radiation protection standards lack limits for band less than 100 KHz (except 50Hz). It makes the electromagnetic radiation assessment of light industrial equipments lack sufficient basis. The electromagnetic radiation protection standard of light industrial equipments was discussed and the limits for electromagnetic radiation protection of light industrial equipments are suggested.

On Three Axes Ganged NC Grinding Machine with Ganged Revolving Spindle

The different uses of NC grinding machine with ganged revolving spindle and the requirements to NC grinding machine for several special uses are discussed. A multifunctional three axes ganged NC grinding machine with patent right is introduced. Its ganged revolving spindle is changeable. Therefore it can meet the requirements of different uses. When the ganged revolving spindle works as headstock spindle, the NC grinding machine can be used for machining cylindrical cam, plate cam, noncircular shaft and so on. When the ganged revolving spindle works as a revolving spindle of dresser, the NC grinding machine can be used for dressing form wheels with multifarious curved generatrices accurately. With simple mechanism, wide flexibility and simple NC programming, it is especially fit for laboratory use. A new-style NC dresser with invention patent right is also introduced.

On Programming for NC Grinding of Grooved Cam with Discretional Plane Curve Profile

In grinding of grooved cam, the programming for NC machining can’t directly be accomplished according to track curve of roller center in working drawing because the diameter of wheel becomes smaller than diameter of cam’s follower roller after wheel dressing. Track curves of wheel center are equidistant curves of the track curve of roller center and they can be gained by equidistant offset. But track curves of wheel center can’t be gained by equidistant offset for grooved cam with discretional plane curve profile, due to the profile including aspheric curves whose equations are usually unknown. To solve above problem, circular arc approximation for the aspheric curve part was realized by using Approximate Double Circular Arc Interpolated Method (ADCAIM), then equidistant offset of circular arcs was carried out by “offset” way, and consequently track curves designed for wheel center of any diameter can expediently be gained on AutoCAD platform. Validation experiment of simulation grinding was fulfilled on a NC milling machine. The experiment results indicate: it is feasible to NC grind grooved cam with discretional plane curve profile using the method introduced in this paper for the example.

On Auto-Programming for NC Machining of Aspheric Curve

Approximate Double Circular Arc Interpolated Method (ADCAIM) has been proposed by the authors. It requires only the included angles in the normal directions of the adjacent arcs at intersection points to be less than specified value, but does not require the adjacent arcs to be tangent as in other circular arc interpolated methods. ADCAIM is an approximate method with better calculating speed because of its concise calculation, and its interpolated error can meet the requirement too. The problems in NC programming of aspheric curves have been solved by using ADCAIM. In this paper, to the plane profile including aspheric curves, using VB program language as the second development tool, auto-programming for NC machining of aspheric curve is also realized by using ADCAIM, as long as the curve’s profile graphics on the AutoCAD is known. The research result indicates: the method introduced in this paper can meet the needs of NC machining in both interpolated accuracy and calculating speed for the example.

Study and Development of Reconfigurable and Multi-Station Auto Shaft Pressing and Assembling Machine for Small Gears

Aiming at the shaft pressing and assembling process for steel shaft and small gear, which is frequent in toy gear reducer assembling, a reconfigurable and multi-station auto shaft pressing and assembling machine had been developed. In the machine, steel shaft and small gear are positioned in a pre-positioned fixture in advance. The assembling process is carried out in three stations simultaneously. It makes the machines efficiency become higher. Applying the reconfigurable design concept, the machine can be divided into basal modules and changeable modules. The changeable modules can be adjusted or replaced to make the machine fit for components of multifarious small gears and steel shafts with different length and diameter. Each module of the machine is introduced in detail and related problems are discussed in the paper.

On Medium Frequency Induction Heating Applied in the Energy-Saving Light Industrial Equipments and its Electromagnetic Radiation

Increasingly, induction heaters are being widely applied to the energy-saving light industrial equipment. But their electromagnetic radiation’s impact on the environment can’t be ignored. In the paper, several medium frequency induction heaters had been studied under different experimental conditions using E61 electromagnetic field strength analyzer, and as its supplement, the racetrack-coils induction heater had been simulated using ANSYS. According to ICNIRP guidelines, the results show that their radiation is generally in critical state, and magnetic field strength is superstandard in some areas. And countermeasures to the problems are advised.

Design and Implementation of the Cutting Dynamometer System Based on Virtual Instrument Technology

On Labview’s development platform, taking full advantage of multithreading management and data stream control, a quick-responding dynamometer system for cutting process is designed and developed based on the Usb interface. The system possesses functions such as data acquisition, signal generation, signal pre-processing, data storage and data analysis, has facile operation interface, and supports data post-processing and analysis well.

NC Programming and Error Discussion in Grinding for Cylindrical Cam’s Groove

The grinding for cylindrical cam’s groove means grinding for groove’s flanks. For cylindrical cam with translating cylindrical followers, an auto-programming system for NC machining of cylindrical cam’s groove is developed. It can be applied to machine cylindrical cam with different types of curve grooves, by using cutter or wheel with different diameter. For validating geometry precision of the auto-programming system, emulation is carried out using the VERICUT, which is a NC machining emulator system. It is showed by the results of the emulation, there is excess of geometry error at bottom of groove when following situations are met: big pressure angle, high precision requirement and big diameter difference between wheel and roller. An important origin of such excess is computational error introduced by the auto-programming system in calculating the coordinates of wheel center.