Golf Club Heads Research Articles

A novel system for tracking iron golf clubheads

The importance of iron play to scoring in golf is widely recognised. To better understand this relationship, accurate, yet unobtrusive measurement techniques are required to capture information about the collision between the golf club and ball. This article presents a method for tracking an iron clubhead prior to impact with the ball. Using repeated shots by a golf robot with a 5-iron and 9-iron, the system reliably measured clubhead speed (standard deviation ≤ 0.5 mile/h), face angle (≤0.2°), club path (≤0.2°), effective loft (≤0.5°), attack angle (≤0.1°) and effective lie (≤0.3°). Impact position was within a standard deviation ≤ 0.6 mm for repeated shots. Absolute accuracy of horizontal impact position at initial contact was <1 mm, whereas a systematic offset of up to 4 mm was found for vertical impact position compared to tests using impact location tape. This offset was dependent on the loft of the club and could be explained by the interaction between ball and club during contact. In addition, a unique feature of the algorithm is presented which categorises impacts commonly known as ‘top’, ‘thin’, ‘good’ or ‘heavy’ shots, which is facilitated through tracking of the bottom edge of the clubhead using virtual markers. Hence, this tracking system is presented as a novel solution to accurately measure clubhead presentation and initial ball impact location for irons.

Effect of Laser Welding Parameters on Weld Bead Geometry

The aim of the study was the development of models that describe Laser beam welding process of maraging steel 250 sheets, based on measured experimental data. Maraging steel 250 is widely used in applications that require high strength steel. For example, in aerospace industry, to produce engine components, or in sports industry, to produce bicycle frames or golf club heads. In order to achieve a reliable and repeatable welding process, we investigated the influence of welding parameters on the welded process responses, i.e., weld penetration depth and bead width. Two modeling techniques for predicting weld bead geometry were developed and tested. One method is the Multiple Regression Analysis (MRA) which is widely used for modeling welding processes and the other is Artificial Intelligence (AI) technique, which is rarely applied for modeling welding processes. The MRA method uses polynomials to express the relations between bead geometry and welding parameters, while the AI method is more flexible and presents in the model terms with physical meaning. Both MRA and AI models present similar statistical quality of fit between the predicted values of bead geometry and the actual experimentally measured data.

Vibration characteristics of golf club heads in their handheld grinding process and potential approaches for reducing the vibration exposure

To control vibration-induced white finger among workers performing the fine grinding of golf club heads, the aims of this study are to clarify the major vibration sources in the grinding process, to identify and understand the basic characteristics of the club head vibration, and to propose potential approaches for reducing the vibration exposure. The vibrations on two typical club heads and two belt grinding machines were measured at a workplace. A simulated test station was also constructed and used to help examine some influencing factors of the club head vibration. This study found that the club head vibration was the combination of the vibration transmitted from the grinding machines and that generated in the grinding process. As a result, any factor that affects the machine vibration, the grinding vibration, and/or the dynamic response of the club head can influence the vibration exposure of the fingers or hands holding the club head in the grinding process. The significant influencing factors identified in the study include testing subject, grinding machine, machine operation speed, drive wheel condition, club head model, mechanical constraints imposed on the club head during the grinding, and machine foot pad. These findings suggest that the vibration exposure can be controlled by reducing the grinding machine vibration, changing the workpiece dynamic properties, and mitigating the vibration transmission in its pathway. Many potential methods for the control are proposed and discussed. Relevance to industryVibrations on handheld workpieces can be effectively transmitted to the hands, especially the fingers. As a result, a major component of the hand-arm vibration syndrome - vibration-induced white finger - has been observed among some workers performing the grinding and/or polishing tasks of the handheld workpieces such as golf club heads. The results of this study can be used to develop more effective methods and technologies to control the vibration exposure of these workers. This may help effectively control this occupational disease.

Mechanical and tribological properties of Zr-based bulk metallic glass for sports applications

The microstructure, and mechanical and tribological properties of zirconium-based bulk metallic glass (Zr-BMG) were investigated for golf club heads. The Zr-BMG had a fully amorphous structure without any detectable crystalline phases. The hardness and Young's modulus of the Zr-BMG were relatively high even though they were lowered by about 36% and 28% respectively by the increased indentation depth from 200 to 1000nm due to strain softening during the nanoindentation test. The tribological behaviour of the Zr-BMG was investigated by sliding against alumina (Al2O3), 100Cr6 steel or polymethyl-methacrylate (PMMA) balls under normal loads of 1–3N. The wear of the Zr-BMG tested against the Al2O3 and 100Cr6 balls became higher with higher normal loads while a higher wear resistance of the Al2O3 ball than that of the 100Cr6 ball caused a higher wear of the Zr-BMG. A much lower wear resistance of the PMMA ball than that of the Zr-BMG resulted in a preferential wear of the PMMA ball without generating any apparent wear of the Zr-BMG during the testing. The Zr-BMG tested against the Al2O3 ball exhibited the highest wear under all the normal loads due to the highest wear resistance of the Al2O3 ball among the counter balls.

Application of Finite Element Methods for the Analysis of Restitution Coefficients for Golf Club Heads

Finite element methods are applied to investigate the coefficient of restitution (COR) for the head of a golf club. ANSYS commercial finite element software is first applied to determine the COR of two different disc-shaped titanium impact surfaces. These values were then experimentally verified to validate the accuracy of the finite element model. Finally, ANSYS was applied to determine the COR for club heads according to USGA specifications to confirm the reliability of the finite element model. The model is then validated by comparison with experimental results. The model can not only reduce time needed for product design and experimental testing, but can serve as a basis for follow-up studies on ball flight trajectory.

Vision-based Assembly and Inspection System for Golf Club Heads

Golf club head production is started by creating metallic films and forming blank casts, which then undergo complex and sophisticated assembly procedures, morphological inspection and strength testing. Not only chemicals used in these processes often threaten the health of operators, but also most of this backend processing involves manual assembly and welding, demanding substantial amounts of manpower. In light of these pitfalls, this paper proposes a Vision-based Assembly and Inspection System for Golf Club Heads (VAIS-GCH) to mitigate the time-consuming and labor-intensive golf club head production process. Two cameras are coordinated to capture top-view image of the striking plate, and top- and side-views of the casting body for visual processing. After the barycenter shift and shifting angle of the striking plate are determined, a robot arm is then directed to suction up the striking plate from the conveyor belt, adjust it to the canonical orientation, and move the yet-to-be assembled striking plate to the top of the casting body. The 3D spatial positions of the casting body, namely, the XYZ shifting angles of the coupling opening, are detected by comparing the top- and side-view images captured with pre-stored 3D golf club head template to facilitate the coupling of the striking plate and casting body. The side-view camera monitors the insertion depth of the striking plate during the coupling process to make sure the surface of the striking plate levels with the casting body. The loft angle, formed by the line perpendicular to the tangent of the bottom of casting body and the tangent of the striking surface, is tested to confirm whether specifications are satisfied. Through the coordination of two cameras, the accuracy and efficiency of the golf club head assembly are increased significantly. The alignment error is smaller than 0.8 mm and the assembly and inspection process takes less than 2 s.

Spark production by abrasion of titanium alloys in golf club heads

SummaryThe objective of the present study was to determine whether golf clubs that have titanium (Ti) alloy surfaces can produce sparks when abraded under normal swing conditions. In the present work, sparks are defined as moving particles that emit radiant energy due to the process of combustion on its surface. Two three‐irons and a three‐wood containing a Ti alloy in the head as well as two three‐irons and a three‐wood that only contain stainless steel in the head were included in the study. The impact events during abrasion testing were recorded using a high‐speed video camera, and abrasion damage was determined using stereometric analysis of scanning electron microscopy images. The findings reveal that Ti alloy faceplates that extend to the sole of the club can produce a number of Ti alloy particles when abraded under swing conditions. The particles then combust for a sufficient duration to potentially ignite a neighboring fuel source such as dry foliage and grasses. Abraded Ti alloy microparticles up to 500 µm in diameter were observed to burn for nearly 1 s, allowing ample time for fuel ignition. By contrast, no sparks were produced by stainless steel club heads when tested under the same conditions. Copyright © 2014 John Wiley & Sons, Ltd.

In Vitro Culture and Rooting of Diospyros virginiana L.

The hard, strong, very close-grained wood of common persimmon (Diospyros virginiana L.; Ebenaceae) is desirable for specialty products such as golf club heads, percussion sticks, billiard cues, and for wood turnery. The edible fruit of cultivated varieties is sold as pulp for use in puddings, cookies, cakes, and custards. Persimmon is usually propagated by grafting. Own-rooted clonal persimmon could offer several advantages to specialty fruit growers such as elimination of grafting, graft incompatibility issues, and improved rootstocks for variety testing. Four mature, grafted (male and female) persimmon genotypes and one hybrid were used for nodal explant culture. Nodal stem explants were cultured on Murashige and Skoog (MS) medium containing 10 μM zeatin, 3% (w/v) sucrose, and 0.7% (w/v) Bacto agar. Explants were routinely transferred to fresh medium every 3 weeks until shoot cultures were established. All nodal explants excised from grafted greenhouse plants produced at least one viable shoot. For in vitro rooting of microshoots, half-strength MS medium with 0, 5, 10, or 15 μM indole-3-butyric acid (IBA), 0.1 g·L−1 phloroglucinol, 3% (w/v) sucrose, and 0.7% (w/v) Bacto agar were tested with a 10-day dark culture treatment followed by culture in the light. Best rooting (14% to 87%) was achieved on medium containing 5 μM IBA for the common persimmon genotypes with means averaging from 0.5 to 3.9 roots per shoot. Ninety-one percent rooting with 5.3 ± 2.6 roots per shoot was achieved for the hybrid persimmon. Rooted plants were successfully acclimatized to the greenhouse.

로봇머신 데이터를 이용한 골프 클럽 피팅

The purpose of this study was to suggest the proper shaft and head fitting methods of the golf club to increase the flight distance of the golf ball. Rotations per minute of the golf ball(RPM), ratio of Ball speed to club head speed(T-Ratio) and launch angle right after impact(LA), which are directly related to ball flight distance, were measured using Spectra with shutter speed of 1/1000sec at the constant head speed of 95mph which was controlled by robot golf swing machine. In order to investigate the effect of club shaft to the 3 selected variables, 10 shafts were used to make ten test clubs with one controlled club head which is the most commonly used by golf players. To measure the effect of the club head to the 3 selected variables, 6 golf club heads which are most commonly used by golfers were selected to make 6 test clubs with a controlled shaft which is one of the best known by players. The shafts and the heads were identified by statistical analysis to increase or decrease the RPM, T-ratio and LA. A proper fitting method of the selected shafts and the club head was suggested to increase the ball flight distance in golf.

Golf Clubs and Golf Club Heads Having Feel Altering Systems

Golf club heads include: (a) a body having a ball-striking face and a rear face, the body defining a cavity; (b) a bridge member extending across the cavity, wherein the bridge member is provided to affect, at least in part, a position of a center of gravity of the club head; and (c) a feel altering element provided between the bridge member and the rear face. The feel altering element may affect a wide variety of parameters that relate to the “feel” of the golf club head when it strikes a golf ball, such as the sound produced by the club head during the strike, the vibrational response of the club head during the strike, the swing characteristics of the club head (e.g., weight, center of gravity position, etc.), and the like.

Extreme Weighted Hybrid And Other Wood-Type Golf Clubs And Golf Club Heads

Wood-type golf club heads include: (a) a club head body member defining an interior chamber; (b) a weight system engaged with a rear perimeter portion of the club head body member; and (c) a connection system connecting the weight system with the club head body (e.g., with the rear of the ball striking face portion). The club heads further may include one or more damping members in the interior chamber to alter the sound and/or otherwise attenuate a vibrational response of the club head. The damping members may extend between the ball striking face and the weight system, and optionally may engage the connection system. The damping member(s) may constitute a foam material compressed within the interior chamber of the club head. Methods of making such golf club head structures also are described.

Vibration damping for hollow golf club heads

An internal vibration damper for hollow golf club heads is disclosed. Of particular concern is vibration of the club sole and crown when the face of the club impacts a golf ball. At least one column extends from the sole to the crown, approximately perpendicular to the surfaces of the sole and crown. The column construction or its mounting acts to dampen and reduce vibrations of the sole and crown toward and apart from each other upon ball impact on the face of the club head.

Golf club head or other ball striking device with modifiable feel characteristics

Ball striking devices, such as golf club heads (including putter heads), include devices within and/or otherwise engaged with the ball striking head that allow users to selectively change the sound and/or other aspects of the “feel” associated with using the ball striking device to strike a ball. In this manner, a user, a club fitter, or the like can freely customize and adjust the sound and/or other aspects of the ball striking device's feel to correspond to a particular user's preferences.

Mechanical properties and microstructure of commercial amorphous golf club heads made of Zr–Ti–Cu–Ni–Be bulk metallic glass

Mechanical properties and microstructures of Zr 41.2Ti 13.8Cu 12.5Ni 10Be 22.5 (numbers indicate at.%) bulk metallic glass taken from commercial golf club heads were investigated at room temperature and 573 K. Transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) indicate that the thin central section of the golf club head is amorphous and the outer rim of the head is crystallized. X-ray diffraction (XRD) analyses revealed the presence of Zr 2Cu, ZrBe 2, Cu 2Ni and BeNi in the rim of the iron head. In the crystallized region, crystalline particles with the size of ∼1 μm were observed. At room temperature, amorphous sample (∼2100 MPa) revealed higher fracture stress than crystallized sample (∼1700 MPa). Crystallized sample fractured in the elastic region whereas the amorphous sample displayed some plasticity corresponding serrated flow before the fracture. The serrated flow region with some plasticity in the amorphous alloy results from strain hardening and repetitive shear band initiation and propagation. The crystallized alloy extracted from the thick part of the club fractured in the elastic region, at a much lower stress level than the amorphous, suggesting that relatively coarse crystal particles formed during cooling cause the brittle fracture. Scanning electron microscope observations revealed that the compressive fracture surface of the samples from the central thin section mainly consisted of vein-like structure, but the samples from the outer rim of the head showed mixture of vein-like structure and featureless brittle fracture morphology. At 573 K, both samples exhibited the decrease of strength and fractured in the elastic region. In this study, the effect of crystallization on the reliability and safety of golf club heads was also examined.

High-temperature deformation behavior and stress relaxation of Zr–Ti–Cu–Ni–Be bulk metallic glass extracted from commercial golf club heads

High-temperature mechanical properties and stress relaxation of amorphous Zr 41.2Ti 13.8Cu 12.5Ni 10Be 22.5 alloy (number indicate at.%) taken from thin sections of commercial golf club heads were investigated at high temperatures. Stress overshooting was observed below the glass transition temperature, and the viscous flow behavior was revealed in the supercooled liquid temperature region. The stress was found to increase after high-temperature interruption due to crystallization at high temperatures. Below the glass transition temperature, not only stress overshooting, but also a stress increase was observed. The presence of stress overshooting may be linked to a stress-induced rearrangement of solute atoms in the matrix of the amorphous phase. The stress relaxation rate below the glass transition temperature was very low whereas it was very fast at temperatures between the glass transition temperature and the crystallization temperature T x. The stress relaxation rate decreases above the crystallization temperature, T x, which can be attributed to the difficult atomic rearrangement and the low diffusivity in intermetallics.

A33 ゴルフクラブのヘッドを模擬した中空体とボールとの衝突解析(ゴルフ2)

A33 ゴルフクラブのヘッドを模擬した中空体とボールとの衝突解析(ゴルフ2)

A study of thickness optimization of golf club heads to maximize release velocity of balls

AbstractIn the present study, the shape optimization of a golf club head is investigated. The problem of maximizing the release velocity of the ball after impact is treated under the constraint of a specified weight of club head. The thickness distribution of the clubface is chosen as the design variable for optimization. The basis vector method, which is an approximating method for optimization problems in which the sensitivity cannot be derived analytically, is employed. The basis vector represents a fundamental change of shape, and it is preferable to obtaining effective results that the basis vectors be mutually independent. A simple approach to create the basis vectors using eigenmodes is also presented. The theory of impedance matching is confirmed numerically by a two‐dimensional example. A three‐dimensional example is given to show that this approach is effective for optimal design of the golf club head. Copyright © 2004 John Wiley & Sons, Ltd.

How to market titanium: Lower the cost

Titanium continues to be referred to as the “wonder metal,” with an image as untarnished as the metal itself; however, cost remains the barrier to greatly expanded use. Titanium is used when it is the only material that will do the job. For example, approximately 45% of the Advanced Tactical Fighter F-22 Raptor is constructed from titanium. It’s also the most effi cient material for construction of other items such as golf club heads. However, with its bright and positive image, titanium also sees use in higherquality consumable items such as watches, bicycles, jewelry, hammers, and knives (Figure 1). State-of-the-art titanium science, technology, and applications were showcased at the Tenth International Titanium Conference in Hamburg, Germany, 13–18 July 2003. Skillfully chaired by Gerd Lutjering, the conference outdid all previous conferences in this series with more than 730 attendees and in excess of 450 papers. All of the major titanium-producing countries were represented at the conference—United States, Commonwealth of Independent States, Japan, United Kingdom, France, China, and Germany. An interesting development here was the high quality of the presentation aids used by all participants—quite a contrast from the hand-drawn slides used by representatives from China and the Commonwealth of Independent States in the past. It was also apparent that the participants from these countries were cognizant of what it takes to market titanium to the West—quality, consistency, strategic alliances—oh, and cost. The cost theme permeated the conference, both in the formal papers and in hallway discussions. Aerospace was no exception here, with the big commercial guys such as Boeing and AirBus turning to titanium castings to reduce cost and in the military arena, U.S. Air Force programs such as the Metals Affordability Initiative and Forging Supplier Initiative aiming at cost-affordability. The high cost of titanium compared to metals such as steel and aluminum comes from the high extraction and processing/fabrication costs for the wonder metal. Papers at the conference addressed both areas of concern. For example, new extraction processes have benefi ted from the infl ux of multimillions of dollars from the Defense Advanced Research Project Agency for techniques such as the Fray-FarthingChen reverse electrolysis approach. In processing, single-melt methods were discussed as well as near-net-shape processes including casting, powder metallurgy (P/M), precision forging, and extrusions. Following the pioneering work by T. Saito in incorporating titanium P/M valves into the Toyota Altezza family automobile fi ve years ago, work in this area appears to be expanding with a greater urgency in Japan and Europe (where gasoline is 3–3.5 times the price it is in the United States). For an update on what’s new in titanium, read the articles featured in this issue of JOM. You’ll note that the papers range from research work on titanium components to dental use of titanium. The articles on titanium in the family automobile and powder metallurgy titanium review the cost issue.

ゴルフ用強靭β‐Ｔｉ合金Ｔｉ‐１５Ｖ‐６Ｃｒ‐４Ａｌの開発

Titanium alloys, high strength and low density materials as compared with steels, have been popularly used for golf club heads of drivers and fairway woods. The advantage of titanium alloys is to realize an oversized club head with a large sweet spot without increasing overall weight of a golf club. So far great effort has been made to produce the oversized golf club head. However, the larger the club head become, the thinner the wall of the club head is required. In order to make the wall thin further, the development of a new titanium alloy that has higher strength and toughness than conventional alloys is necessary. In this study, to develop a new beta-titanium alloy for the golf club heads, optimization of chemical composition of a Ti-V-Cr-Al alloy system was carried out based on a conventional beta titanium alloy Ti-22V-4Al. Chromium, one of the solid solution strengthening elements of the beta phase, was employed to enhance the strength of alloys. Vanadium content was optimized to obtain good ductility and to control age hardening speed. After the solution and aging treatment, one of the designed alloys, Ti-15V-6Cr-4Al, showed excellent combination of strength and toughness as compared with conventional beta alloy Ti-22V-4Al. Further, the combination between tensile strength and ductility of this alloy was improved by cold working and age-hardening. The performance test of golf club heads fabricated by this developed alloy Ti-15V-6Cr-4Al revealed good durability as compared with conventional alloy heads made by Ti-22V-4Al and Ti-15V-3Al-3Cr-3Sn.

A comparison of the mechanisms of fatigue-crack propagation behavior in a Zr-based bulk amorphous metal in air and an aqueous chloride solution

Bulk amorphous alloys, such as the Zr 41.2Ti 13.8Cu 12.5Ni 10Be 22.5 (at.%) alloy, have received much interest lately, particularly for their commercial application in golf club heads. This study seeks to investigate the fatigue behavior of this Zr-based amorphous metal in the presence of air and sodium chloride solution, with the specific goal of identifying mechanisms of environmentally assisted fatigue-crack growth in these environments. Results from experiments, including fatigue testing in air and sodium chloride, fatigue under potential control, and static load testing in sodium chloride, suggest that quite distinct mechanisms of fatigue-crack propagation are active in air and sodium chloride solution. Specifically, the fatigue-crack growth rates observed under static and cyclic loading in sodium chloride likely depend on an anodic process, which results in a brittle mode of failure. Conversely in air, fatigue-crack propagation is associated with alternating blunting and re-sharpening of the crack tip, as evidenced by the presence of classic fatigue striations.