Search results

The purpose of this study is to present the implementation of Six Sigma in a solenoid valve manufacturing company in China. The project aims to reduce the solenoid valve defects, decrease the cost of poor quality, increase customer satisfaction and improve the long-term profitability of Company B.

This paper follows the Six Sigma methodology: DMAIC (define, measure, analyse, improve and control) principle of case study research. Hysteresis, the key characteristic of a solenoid valve, is the main chance for quality improvement. This paper emphasizes the solution to the hysteresis problem. During DMAIC phases, the critical factors that affect hysteresis performance are identified for continuous quality improvement of solenoid valve manufacturing.

The implementation of Six Sigma leads to a great quality improvement for the company studied in this paper. Control plans are made for good hysteresis performance. As a result, the first pass yield of solenoid valves has increased from 60% to 99.64%. The key hysteresis of the solenoid valve has shown a better performance.

This study presents a solenoid valve industrial quality improvement case that demonstrates how Six Sigma and DMAIC methodology can be applied to reduce defects and achieve quality improvement in Company B. This study can be referred to for managers and engineers to undertake quality improvement programs.

The purpose of this paper is to develop a cyclone with an internal electric field to capture dust and fine carbon particles with less than 5 μm diameter.

The cyclone collection efficiency model described by Cooper and Alley was used to design a conventional cyclone, which was later modified by introduction of the solenoid around it to introduce an electric field. The cyclone design performance was later established using ferrosilicon powder with less than 5 μm diameter.

The cyclone was found to have a particle collection efficiency of around 25 per cent for ferrosilicon powder before the introduction of the solenoid; the introduction of the solenoid increased the particle collection efficiency to around 50 per cent and the charging of the solenoid further increased the collection efficiency to 85 per cent at 2 kV DC and 97 per cent at 3 kV DC. When the cyclone was placed back on the gasifier system and supplied with 2 kV DC, it collected up to 270 g of fine carbon particles within 150 min of operation.

The major drawback was that the highest particle collection efficiency for the cyclone could only be achieved at very high voltage (3 kV) but this could not be supplied when the cyclone was back in the gasifier system due to air ionization that results in the corona effect.

The collection of very fine particles (less than 5 μm diameter) in hot gas streams is always a challenge, particularly in biomass gasifier systems. This resulted in a high cost of gas purification or initial investments in downstream processes. The developed cyclone could cut down this expenditure since most of the particles will not go beyond the cyclone.

Electrostatics has been applied in the development of gas cleaning devices, however most of these devices tend to be too cumbersome. The developed cyclone is based on the conventional design, which is less complicated and cheap to manufacture.

This paper aims to investigate the influence of structure parameters on giant-magnetoimpedance (GMI) effect measured by non-contact method.

The GMI sensor contains a Co-based internal magnetic core fabricated by laser cutting and an external solenoid. The influences of magnetic permeability of magnetic core and structure parameters on GMI effect were calculated in theoretical model. The output impedance, resistance, reactance and GMI ratio were measured by non-contact method using impedance analyzer.

Enhancing external magnetic field intensity can decrease the magnetic permeability of core, which has vital influences on the magnetic property and the output response of GMI sensor. In addition, increasing the width of magnetic core and the number of solenoid turns can increase the maximum GMI ratio. The maximum GMI ratio is 3,230% with core width of 6 mm and solenoid turns of 200.

Comparing with traditional contact-measured GMI sensor, the maximum GMI ratio and the magnetic field sensitivity are improved and the power consumption is decreased in non-contact measured GMI sensor. GMI sensor measured by non-contact method has a wide range of potential applications in ultra-sensitive magnetic field detection.

The Purpose of this study is to prove the possibility of developing low cost mechanical anti – lock braking system (ABS) for the passenger’s safety.

The design methodology of the proposed newer mechanical ABS comprises of two units, namely, the braking unit and wheel lock prevention unit. The braking unit actuates the wheel stopping as and when the driver applies the brake, whereas the wheel lock prevention unit initiates wheel release to prevent locking and subsequent slip/skidding. The brake pedal with master cylinder assembly and double-arm cylinder forms the braking unit, brake pad cylinder, movable brake pad, solenoid valve and dynamo forms the wheel lock prevention unit. The dynamo coupled with the rotor energises/de-energises the solenoid values to direct airflow for applying brake and release it, which makes the system less energy-dependent.

The braking unit aids in vehicle stops, by locking the disc with the brake pad actuated by a double-arm cylinder. The dynamo energises the solenoid valve to activate the brake pad cylinder piston for applying the brake on the disc. Instantaneously, on applying the brake the dynamo de-energises the solenoid to divert the pneumatic flow for retracting the brake pad thereby minimizing the braking torque. The baking torque reduction revives the wheel rotating and prevents slip/skidding.

Mechanical ABS preventing wheel lock by torque reduction principle is a novel method that has not been evolved so far. The system was designed with repair/replacement of the parts and subcomponents to support higher affordability on safety grounds.

In the trend from mass production to mass customization, more flexible production systems are required. In the clothing field, many studies about automatization of sewing processes have been done into producing small amounts of various kinds of products. The purpose of this paper is to propose a versatile guiding mechanism of a cloth for an automatic sewing system.

Real sewing processes were referenced for the mechanism, and curved stitch is formed holding a point on a cloth. This mechanism consists of a solenoid for holding a cloth and a roller to prevent deformation of the cloth. When a cloth is sewn with the mechanism, the trajectory of the stitch is unstable because of anisotropy of a cloth. A precise trajectory was obtained by adding a device to control the pressure of the roller for holding a cloth and keeping a tension properly applied to a cloth.

It was found out that shearing property is the most related to the stability of sewing trajectory. If the tension for guidance applied to a cloth is constant, deformation of the cloth was observed and it was the cause of unstableness of sewing trajectory. By controlling the tension for guidance applied to a cloth properly according to the direction of the cloth, precise sewing trajectory was obtained.

There have been some studies in which sewing conditions were dynamically controlled according to the mechanical properties of a cloth. To these studies, here it was proposed that sewing conditions were kept constant by controlling the guidance of a cloth according to its mechanical properties.

The purpose of this paper is to compare several methods to calculate solenoid inductances regarding their applicability to model the inductance of DC motor armature windings. Special attention is given to the influence of wiring insulation and current distribution and the axial length of the solenoid.

Expressions for the self‐ and mutual‐inductance of current filament and wire combinations are derived from basic inductance formulas. Combining these expressions allows expressing the inductance of arbitrary shaped solenoids (e.g. polygons).

Accurately describing self‐ and mutual‐inductances is a very complex topic. However, in the case of motor armature windings, several simplifications can be applied to lower the calculation cost significantly. Plus, differences in inductances between regular polygonial solenoids and similar circular shapes were found to be rather small. Thus, many windings' inductances can well be approximated by using expressions for circular solenoids.

A new way to calculate the inductance of arbitrary polygonial shapes is presented, and an example is given for hexagonal shapes.

In a constant speed, variable pitch propeller an over‐ride device is automatically brought into operation to move the blades to the feathering position when the power unit stops, and means are provided by which the over‐ride is automatically put out of action when an attempt is made to start the power unit by ‘wind‐milling’, and by which the over‐ride is automatically restored when the speed rises to that at which the unit should be self‐operating. When the power unit stops a governor 23 allows a spring 22 to force a valve 19 to the left, thereby allowing motive fluid from a pipe 12 to flow into the left‐hand end of a cylinder 16 to operate a plunger 15 which moves the propeller blades 13 to the minimum pitch position. The resultant change of torque acting on a torque meter 39 closes a switch 37 to complete an electrical circuit for actuating a solenoid 35 controlling a valve 34 which allows motive fluid to be applied from pipe 31 to the spring‐loaded plunger 28 of the over‐ride device. The plunger moves the valve 19 to the right, allowing fluid into the right‐hand end of cylinder 16, thereby moving the blades to the feathering poistion. The circuit may also be completed by the pilot closing the fuel isolator valve 36. To start the power unti by wind‐milling, ignition switch 46 of the power unit is closed, the govenor controlled switch 47 being already closed. A solenoid 45 then opens a switch 44 and breaks the circuit to the solenoid 35 so that the valve 34 closes to cut‐off the supply of fluid to the over‐ride plunger. The spring 22 is thus able to move the valve 19 to the left with the result that the blades are moved from the feathered position to cause ‘wind‐milling’. If at a predetermined speed the unit does not then become self‐operating, its governor will open the switch 47 causing switch 44 to close to complete the circuit to the solenoid 35. The valve 34 will be raised to bring the over‐ride into operation, causing plunger 28 to move valve 19 so that the propeller blades are moved to the feathered position.

An actuating unit for an aircraft remotely controlled element, comprising a motor including a drive shaft and a pair of field coils for rotating said shaft in opposite directions, an output shaft, complemental jaw clutch elements between said shafts, said clutch elements being adapted to be engaged to establish the driving relation between said shafts and disengaged to break the driving relation, a solenoid controlling said jaw elements, a solenoid switch for each of said field coils, a pair of spaced limit switches operatively connected to said solenoid and solenoid switches, a member movable between said limit switches to actuate one or the other, means drivably connected to said output shaft to cause movement of said member to engage one of said limit switches after a predetermined number of revolutions of said output shaft, contact means included in the circuit of said solenoid switches, and means to control said contact means from said jaw clutch elements whereby engagement of said clutch elements makes the contact and disengagement of the clutch elements breaks the contact.

Due to their high magnetizing field requirement, the emergence of rare‐earth based permanent magnets is creating onerous demands on the capacitor‐discharge systems which are used for their initial magnetization, a process which is aggravated by the fact that the transient current pulse induces eddy currents, which inhibit the penetration of the magnetizing field, and causes heating and stressing of the magnetizing fixture. The problems are compounded in multi‐pole and post‐assembly magnetization systems, particularly for fine pole‐pitch fields. However this paper concentrates on the pre‐magnetization of magnets in air‐cored solenoids, which, despite the difficulty in subsequently handling magnetized magnets, remains the most common requirement. It presents a methodology for the design of impulse magnetizing solenoids to produce the amplitude and time to peak of magnetizing field required for a specific generic type and aspect ratio of magnet to be magnetized, and describes a procedure for the subsequent analysis of the complete impulse magnetization system.

The purpose of this paper is to design an improved parallel regenerative braking system (IPRBS) for electric vehicles (EVs) that increases energy recovery with a constant brake pedal feel (BPF).

The conventional hydro-mechanical braking system is redesigned by incorporating a reversing linear solenoid (RLS) and allowed to work in parallel with a regenerative brake. A braking algorithm is proposed, and correspondingly, a control system is designed for the IPRBS for its proper functioning, and a mathematical model is formulated considering vehicle drive during braking. The effectiveness of IPRBS is studied by analyzing two aspects of regenerative braking (BPF and regenerative efficiency) and the impact of regenerative braking contribution to range extension and energy consumption reduction under European Union Urban Driving Cycle (ECE).

IPRBS is found to maintain a constant BPF in terms of deceleration rate vs pedal displacement during the entire braking period irrespective of speed change and deceleration rate. The regenerative ratio of IPRBS is found to be high compared with conventional parallel regenerative braking, but it is quite the same at high deceleration.

A constant BPF is achieved by introducing an RLS between the input pushrod and booster input rod with appropriate controller design. Comparative analysis of energy regenerated under different regenerative conditions establishes the originality of IPRBS. An average contribution ratio to energy consumption reduction and driving range extension of IPRBS in ECE are obtained as 18.38 and 22.76, respectively.