To maximise productivity and reduce scrap in high-value, low-volume production, five-axis machine tool (5A-MT) motion accuracy must be verified quickly and reliably. Numerous metrology instruments have been developed to measure errors arising from geometric imperfections within and between machine tool axes (amongst other sources). One example is the TMBB, which is becoming an increasingly popular instrument to measure both linear and rotary axis errors. This research proposes new TMBB measurement technique to rapidly, accurately and reliably measure all position-independent rotary axis errors in a 5A-MT. In this research two literature reviews have been conducted. The findings informed the subsequent development of a virtual machine tool (VMT). This VMT was used to capture the effects of rotary and linear axis position-independent geometric errors, and apparatus set-up errors on a variety of candidate measurement routines. This new knowledge then informed the design of an experimental methodology to capture specific phenomena that were observed within the VMT on a commercial 5A-MT. Finally, statistical analysis of experimental measurements facilitated a quantification of the repeatability, strengths and limitations of the final testing method concept. The major contribution of this research is the development of a single set-up testing procedure to identify all 5A-MT rotary axis location errors, whilst remaining robust in the presence of set-up and linear axis location errors. Additionally, a novel variance-based sensitivity analysis approach was used to design testing procedures. By considering the effects of extraneous error sources (set-up and linear location) in the design and validation phases, an added robustness was introduced. Furthermore, this research marks the first usage of Monte Carlo uncertainty analysis in conjunction with rotary axis TMBB testing. Experimental evidence has shown that the proposed corrections for set-up and linear axis errors are highly effective and completely indispensable in rotary axis testing of this kind. However, further development of the single set-up method is necessary, as geometric errors cannot always be measured identically at different testing locations. This has highlighted the importance of considering the influences on 5A-MT component errors on testing results, as the machine tool axes cannot necessarily be modelled as straight lines.

The annual cost of corrosion in the United States Navy and Coast Guard is in excess of $2.7 billion dollars. The salt water environment provides a ripe surrounding for rapid corrosion and deterioration of ship decking, which requires frequent and expensive maintenance. Decks of ships are susceptible to corrosion and wear, but must also maintain a non-slip surface in a constantly wet environment. Few options for non-skid deck materials are currently approved for use by the Navy and require frequent and expensive maintenance or replacement. A new material known as Laser Deposited Non-Skid, currently used in industrial flooring applications, shows potential for serving as a more durable non-skid material with extended service life and greater resistance to corrosion. The purpose of this research is to investigate the feasibility of Laser Deposited Non-Skid in decks of ships and to compare the corrosion, wear and cost data with existing deck materials. Sample plates of A36 and A572 steel and 5086 and 5456 marine grade aluminum alloy were coated with selected non-skid materials and subjected to laboratory salt fog testing and corrosion in environmental conditions in the Caribbean Sea. Wear behavior among non-skid materials was evaluated through wear cycles, measurement of coefficient of friction, and surface characterization. Salt fog testing was more corrosive than the actual operational environment in all cases and the Laser Deposited Non-Skid samples had the best resistance to wear and corrosion. The Peel and Stick Non-Skid demonstrated corrosion by undercutting while the Traditional Non-Skid corroded through the material. The relative area did not correlate well with friction or wear mass loss. Aluminum Laser Deposited Non-Skid appears suitable for use as a deck material on small boats. More research is needed to evaluate maintenance issues and possible stress cracking associated with the Laser Deposited Non-Skid on steel decks.

Surface metrology has been widely used in manufacturing for many years. There has been a wide range of techniques applied for measuring surface topography. A photometric stereo technique is one of the best ways for the analysis of three-dimensional (3D) surface textural patterns. Many published works are concerned the developed approach for recovering the 3D profiles from surface normal. This research not only presents a methodology used to retrieve the profiles of surface roughness standards but also investigates the uncertainty estimation of textural measurement determined by the photometric stereo method. Various input quantities have been studied such as pixel error from recovered 3D surface textural patterns, the power of light source which involved with surface roughness average (Ra) value and the effect of room temperature. The surface roughness standards were utilized as the reference value. In term of increasing accuracy of the reference value, a contact method (stylus instrument) was used to calibrate them. Illumination angles of light source had some influence on the measurement results. A coordinate measuring machine (CMM) was used for holding the light source in order to study the effects of tilt and slant angles. The effect of tilt and slant angles were investigated. The results of these experiments successfully indicated that the angle used in photometric stereo method played an important role to the accuracy level of the roughness measurement results. The surface roughness specimen manufactured by a Computer Numerical Control (CNC) was applied to validate the capability of the photometric stereo system.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains viii, 58 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 55-58).

No description available.

In recent years, the manufacturing industry has seen an increase in demand for micro-components in biomedical, opto-mechatronics, and automotive applications. Traditional machine tools are no longer a viable solution to meet the tolerances required by the customers. Hence, new ultra-precision machine tools have emerged with nanometer level accuracy in response to these demands. This thesis presents a novel ultra-precision machine tool with the intent to bridge the gap between traditional machine tools with larger work volumes and lower accuracy, and ultra-precision machine tools with high accuracy and small work volumes. The machine was designed using a T-type gantry and worktable configuration with a precision ground granite base, to achieve a work area of 300x300 mm2, with a maximum velocity of 1 m/s and a maximum acceleration of 10 m/s2. Actuation is provided by direct drive linear motors with high resolution feedback supplied by 4 µm grating linear encoders with 4096x interpolation. Aerostatic porous bearings are employed to reduce the effect of friction while maintain high stiffness of the guideways and structure. A Vacuum Pre-Loaded (VPL) air bearing supports the worktable on the granite, decoupling vertical load from the gantry. Thermal error reduction is achieved using environmental temperature control (20 ± 0.2°C) to help reduce thermal errors. As well, internally cooled couplings were designed to remove heat generated by the motors, thus further reducing the effects that contribute to thermal error. The target static stiffness of the machine was 50 N/µm and was measured to be 22.2 N/µm and 23.9 N/µm in the x and y axes respectively. Frequency response experiments were used to identify the open-loop transfer functions for each axis. A multivariable framework was implemented for the y-axis due to the cross coupling between the primary and secondary motors of the gantry. Two prominent vibration modes were identified at 68 Hz and 344 Hz. The first mode is attributed to the rigid body yaw mode of the gantry while the higher frequency is related to the bending mode of the beam. The first mode of the x-axis is seen at 220 Hz. A state space, active mode compensation control law was developed for the y-axis, in collaboration with Mr. Daniel Gordon, which eliminates the effects of the 68 Hz mode, allowing for high performance from the motors. The following error during a high speed (200 mm/s) test was measured at 2.74 µm and 2.41 µm in the x and y axes respectively. Metrology tests using laser interferometry were performed in accordance with international and American metrology standards for linear positioning, vertical and horizontal straightness, and yaw and pitch errors. The results will be used for geometric error compensation in future work. Finally, an overall error budget is presented with focus on the geometric, dynamic, servo, and thermal errors, where the maximum static resultant error of the machine was estimated to be 1.44 µm, and the maximum dynamic resultant error of 3.69 µm.

In recent years, the manufacturing industry has seen an increase in demand for micro-components in biomedical, opto-mechatronics, and automotive applications. Traditional machine tools are no longer a viable solution to meet the tolerances required by the customers. Hence, new ultra-precision machine tools have emerged with nanometer level accuracy in response to these demands. This thesis presents a novel ultra-precision machine tool with the intent to bridge the gap between traditional machine tools with larger work volumes and lower accuracy, and ultra-precision machine tools with high accuracy and small work volumes. The machine was designed using a T-type gantry and worktable configuration with a precision ground granite base, to achieve a work area of 300x300 mm2, with a maximum velocity of 1 m/s and a maximum acceleration of 10 m/s2. Actuation is provided by direct drive linear motors with high resolution feedback supplied by 4 µm grating linear encoders with 4096x interpolation. Aerostatic porous bearings are employed to reduce the effect of friction while maintain high stiffness of the guideways and structure. A Vacuum Pre-Loaded (VPL) air bearing supports the worktable on the granite, decoupling vertical load from the gantry. Thermal error reduction is achieved using environmental temperature control (20 ± 0.2°C) to help reduce thermal errors. As well, internally cooled couplings were designed to remove heat generated by the motors, thus further reducing the effects that contribute to thermal error. The target static stiffness of the machine was 50 N/µm and was measured to be 22.2 N/µm and 23.9 N/µm in the x and y axes respectively. Frequency response experiments were used to identify the open-loop transfer functions for each axis. A multivariable framework was implemented for the y-axis due to the cross coupling between the primary and secondary motors of the gantry. Two prominent vibration modes were identified at 68 Hz and 344 Hz. The first mode is attributed to the rigid body yaw mode of the gantry while the higher frequency is related to the bending mode of the beam. The first mode of the x-axis is seen at 220 Hz. A state space, active mode compensation control law was developed for the y-axis, in collaboration with Mr. Daniel Gordon, which eliminates the effects of the 68 Hz mode, allowing for high performance from the motors. The following error during a high speed (200 mm/s) test was measured at 2.74 µm and 2.41 µm in the x and y axes respectively. Metrology tests using laser interferometry were performed in accordance with international and American metrology standards for linear positioning, vertical and horizontal straightness, and yaw and pitch errors. The results will be used for geometric error compensation in future work. Finally, an overall error budget is presented with focus on the geometric, dynamic, servo, and thermal errors, where the maximum static resultant error of the machine was estimated to be 1.44 µm, and the maximum dynamic resultant error of 3.69 µm.

No description available.

Profile waviness is one of the main causes for scrapped parts in precision bore grinding. Although efforts have been made to reduce its occurrence, the problem has not been eliminated completely. In production, the identification of a few scrapped parts in a lot of several thousands often requires expensive manual processes. Grinding machines used to produce these parts are usually equipped with measurement gage heads having tactile probes. Until now, these in-process gages have been used to measure only the average diameter of the part. This research focused on the use of these tactile probes to measure bore waviness in precision-ground parts. The first objective was to develop a post-process machine that performs automated measurement of the bore profile and is capable of detecting waviness. The machine was built using the same measurement system and the same roll-shoe centerless fixture as the grinding machines used for the production of the parts. The machine was designed and set up such that disturbances of the measurement are minimized. It was shown that the machine reaches accuracies close to those obtained by manually operated roundness machines. The cycle time is approximately 4 seconds per part compared to several minutes for manually operated roundness machines. As a second objective, the possibility of measuring waviness directly in the grinding machine was evaluated. Feasible design modifications to reduce the effect of disturbances are very limited in grinding machines, since interference with the grinding process must be avoided. Therefore, analytical methods were developed to reduce these effects and partly restore the original profile. The main disturbances that were addressed are errors due to irregular sampling of the profile, to the frequency response behavior of the gage heads, and to motion of the workpiece center relative to the gage heads. The post-process machine was used as a development and test platform for the analytical methods. To further verify these methods, tests were also conducted in an industrial grinding machine.

No description available.