Dissertations / Theses on the topic 'Thermal Processing of the Ball Screw'

The aim of this thesis is ball screw service life measurement. Text is divided on two major parts, theoretical one and practical one. Theoretical part describes three basic methods of ball screws manufacturing – rolling, whirling and grinding. Subsequently, methods of heat treatment (inductive and laser hardening) are mentioned. Practical part is devoted to ball screw service life testing and evaluation of results. Tests were carried out on two sets of two ball screws. First set was manufactured by whirling and grinding followed by inductive hardening. Second set was manufactured by grinding followed by inductive hardening in one case and laser hardening in the second one. Test results were evaluated according to international standards.

In the modern global economy, there is a demand for high precision in manufacture as competitive pressures drive businesses to seek greater productivity. This results in a demand for a reduction in the errors associated with CNC machine tools. To this end, it is useful to develop a greater understanding of the mechanisms which give rise to errors in machine tool drives. This programme of research covers the geometric, thermal and load errors commonly encountered on CNC machine tools. Several mathematical models have been developed or extended which enable a deeper understanding of the interaction between these errors, various details of ballscrew design and the dynamic behaviour of ballscrew driven systems. Some useful models based on the discrete matter or “lumped mass” approach have been devised. One extends the classical eigenvalue method for finding the natural frequencies and other dynamic characteristics of ballscrew systems to include viscous damping effects using a generalised eigenvalue approach. This gives the damping coefficient of each predicted vibration mode along with the estimates of the natural frequencies, enabling many of the natural frequencies predicted by standard undamped natural frequency analyses to be dismissed as being of little consequence to the vibratory behaviour of the system. A development of this modelling method gives the sensitivity of the system to changes in stiffness and damping characteristics, which is helpful at the preliminary design stage of a ballscrew system, and is an aid in deciding the most convenient remedy to vibration problems which may occur in service. The second set of lumped-mass models is specially developed to take account of the changes in the configuration of the system with time as the nut moves along the screw while taking into account the non-linear phenomena of backlash and Coulomb friction. These can deal with the axial, torsional and transverse degrees of freedom of the system and predict many aspects of the dynamic behaviour of a ballscrew system which have an effect on the errors arising from such systems. They also include features which calculate the energy converted to heat by all the energy dissipative mechanisms in the model which can be used in conjunction with models already developed at the University of Huddersfield to predict thermal errors. Further, a strategy for compensation of some of these errors has been devised

碩士
國立雲林科技大學
機械工程系碩士班
99
The important factors of feed system determine the axial positioning accuracy in machine tools, if considers to the cost, travel, rigidity, and loading, the ball screw that have diverse characteristic simultaneously, and often be used in one kind of drive element. In recent years, in order to promote the working efficiency of machine tool, feed system has gradual high speed''s turning, immediately raise to the request of accuracy. However, when screw in high speed to feed, screw with roll ball rubbing cause screw to inflate and elongation because of thermal, this expansion quantity will have the error to location when the machine to move. To improve what temperature rise causes thermal displacement, usually adopt thermal displacement compensation technology have more economic efficiency. This thesis primarily focus on developing a set of immediately thermal displacement compensation system, reduces the influence of ball screw temperature rise influence of the machine displacement. To establish immediately thermal displacement compensation system, needs the complete thermal displacement and the temperature experiment datum. In order to give dual attention to screw dynamic of multi-spots measurement, the consideration of sub-micron class resolution and the non-contact measurement method, This article takes the thermal displacement measuring instrument by the laser interferometer, and imbed the temperature sensor into the screw nut to measure the screw temperature rise. Finally uses Ivakhnenko’s propose that Abductive nerves network mode constructs between the temperature and the thermal displacement relationship, and establishes a set of complete thermal displacement compensation program to link to the value controller. To achieve the real-time compensation of temperature rise influence of the machine displacement.

碩士
國立彰化師範大學
電機工程學系
99
Abstract Most of metal processing industries in developing countries or in developed countries are facing the situation of being not able to compete with those in the underdeveloped countries such as China, India, etc., who have cheap labor cost. During past five to ten years, those metal processing industries were a huge loss of orders, as well as their jobs. To survive in their countries, their only solution is to shorten processing hours, increase efficiency and accuracy of the products. To achieve this goal, there has been a lot of high-speed machining technology introduced. In the meantime, high-speed machining technology becomes more and more important for machine tool manufacturing industry, particularly in the high-speed machining centers. To meet the demand for high-speed machining technology, the axes are designed to achieve fast feed. However, ball-screws generate thermal expansion due to high speed movement, thus decrease axis positioning accuracy and increase tolerance. To reduce the tolerance, nowadays there are three solutions. Firstly, the ball-screw is pre-tensioned to compensate the error. However, this solution has limited effect. Second, an improved hollow-shaft ball-screw cooled with chiller is used to keep ball-screw temperature low enough to prevent its thermal expansion. However, such design costs a lot and makes the manufacturing procedure complicated. Third, a closed loop position feedback device is used to read the position on optical scale and feedback value to the CNC controller. Position is no more fed back from axis servo motor encoder, in other words, ball-screw expansion will not affect the precision. However, the system generated high increase in the cost of the machine; thus losing competitiveness. This study proposes an eddy current displacement sensor for the detection unit to measure the displacement of a ball-screw directly. The measured signal is transferred to analog voltage by a transducer and it is sent to the computer numerical control. Then, through programmable logic control program, it is converted to the expanse distance. Next, an opposite direction axis movement is calculated by the computer numerical control for the compensating axial displacement. The experiments are to follow the circular test apparatus and laser interferometer to the axial feeding circularity and positioning accuracy. The measurement results show that roundness progresses by the 8.2μm to 5.2μm, and positioning accuracy improves from the 3.106μm to 2.168μm. Moreover, material and assembly cost of this study is around NT$10,000.00. To compare to the hollow ball-screw cooling system or close loop position feedback system, machine tool manufacturers can save the entire machine cost around 4% to 15%, depend on machine sizes. This study provides effective and competitive way to improve the quality for high-speed and high-precision machine and offer added-value on machine tools. It hopes to enter high value machine tools market level as Japanese, German and other European countries’ products; it gets further away from those products of mainland China, India, etc., which compete strongly with low price. It helps machine tool manufacturer to find a sustainable way.

碩士
國立中正大學
機械系
88
An Abstract The high-speed cutting is most important topic in machine tool industrial in pass few years, by new tooling technology, the cutter surface speed are 5~8 time increasing than before。 To match the new tooling technology, most of machine tool manufactures are research in high speed spindle、transmission system、CNC controller and servo system。 To increase Rapid feed and cutting feed, the Linear motor are used to replace rotary motor & ball screw system for high end machines in few manufactures, but middle and low end machines still stay with ball screw system, because cost concern。 Ball screw nut pre-load can reduce back-lash and increase rigidity in ball screw system, but higher pre-load or higher screw rotation speed or higher loading both will generated more heat between screw、ball、nut by friction。 The position accuracy and repeatability are fair when heat generate in ball screw and causing thermal expansion。 Measuring the temperature change in screw & nut surface and screw expansion rate in different moving speed (2500, 5000, 7500, 10000 mm/min.), Used inverse method to build up system warm up model & equations。 Based on the model and equations to evaluated ball screw expansion rate, and comparison with reading to modify parameters to get better result。 The results are showing linear relation between expansion rate and temperature raise both in screw and nut, based on the temperature feed back from screw nut, to forecast ball screw average temperature and thermal expansion rate to compensate the error of positioning。 The positioning and repeatability accuracy are up grade in limit cost increasing 。

碩士
國立虎尾科技大學
機械與機電工程研究所
102
The ball screw is a precision mechanical transmission component, because the ball in the track motion is not only pure rolling, but also rolling and sliding at the same time. When sliding occurs, the ball contact with the track surface will generate friction heat, especially at high transmission conditions, so that the nut and the screw temperature increased significantly, the main reason for affecting on thermal deformation, led to a significant decline in positioning accuracy. Therefore, this paper used the finite element analysis software (Ansys Workbench) to establish nut thermal analysis model. At first ,the boundary condition takes kinematics theory of ball screw into consideration, and therefore we’d be able to calculate all sorts of parameter such as contact angle, normal force, friction coefficient and sliding speed between the ball and screw, and we also take considered on transmission acceleration, constant and deceleration of the ball screw into consideration, then we can calculate the average heat flux on contact surface of the ball on the track, Secondly, consider setting the nut affected by forced air cooling convection in reciprocation. The nut thermal analysis model can predict the nut''s temperature variation after temperature raised, and explore strain of the nut surface with thermal effect generated nut deformation on different temperature raised. In the experiments, a vertical motion of the single axial screw testing machine to run tests on ball screw, and an additional thermocouple and strain gage is placed on surface of nut, which allows us to gain instant information of the temperature and strain variation of the nut. The results of our experiment are than being compared with the simulated results to increase the reliability of this paper''s construct. Heat transfer conditions at contact surfaces of nut and air, and the other fixed component are also set as boundary conditions. Thermal analysis model can be used in the basis of the ball screw''s nut temperature control design and thermal displacement compensation mechanism.

碩士
國立成功大學
奈米科技暨微系統工程研究所
97
Most of the positioning errors of ball screws come from thermal deformation. The working temperature of the lubricant renders the lubricant film ineffective, and the temperature would continue to rise. This master thesis (1st part) focuses on lubricating ball screws to study the thermal distribution of nuts through an appropriate heat analyzing model. The heat source model derived from sliding and rolling velocities of a ball’s motion would be the first time such a heat source generated from friction is modeled under lubricating conditions of kinematics. Specifically, we consider the relationship between the temperature and viscosity of lubricant, and include it in our simulated flow chart so as to construct a complete thermal analytic model of nuts. In the second part, we measure the temperature from only three operating conditions and take the root mean square error method with the experimental results and the thermal analyzing model from the first part. According to procedure, we can find the predicting curve of the convection coefficient on the groove, and use it in conjunction with the thermal analyzing model to forecast the temperature distribution of nuts at other revolution speeds. 【1st Part】 A preload was added to improve the rigidity and position accuracy of the ball screws. However, more preload will induce increased friction between moving and stationary elements as well as drastic temperature rise. This results in thermal deformation, one of the major accuracy errors of ball screws. In this thesis, we used FEM to construct a thermal analyzing model of nuts under lubricating conditions. The distinguishing point of this thesis is modeling the heat source using kinematic theory, such as average heat flux, average contact band, etc. The appropriate heat source boundary conditions for constructing a heat source model were derived from sliding and rolling velocities of moving balls. The thermal distribution of the nuts would be obtained from the FEM analysis with appropriate boundary conditions. We then considered the relation between the lubricant’s temperature and viscosity, and included it in our simulated flow chart to build a complete thermal analytic model of nuts. 【2nd Part】The lubricant, especially it viscosity, is very sensitive to the ball screws’ working temperature. The operating and lubricating conditions affect the working temperature rise as well. Therefore, we measured the temperature inside the nuts by embedding six thermocouples in drilled holes filled with silver powder. Using the root mean square error method along with the heat analyzing model and experimental results, we can identify the predicting curve of the convection coefficient on the groove with varying revolution speeds. We can thus forecast the temperature of nuts under other speeds after only measuring three operating temperatures.

碩士
國立勤益科技大學
電子工程系
99
Abstract The development of machine centers has a long history. The demand for machine tools with high speed and high precision is the international trend and the users of machine centers also claim higher precision and reliability. During high-speed processing, the axial displacement will produce rapid changes in temperature, and temperature changes will cause thermal elongation on ball screws. There are currently ways either to use hollow screws with cooling systems which can control temperature changes or to install a linear scale for correcting the elongation of the ball screw caused by heat. However, these two designs cost more. Although the temperature compensation technology has caught much attention in recent years, the effect is far from perfect, and the cost is still high. In the future, as higher-speed machine centers are running, thermal elongation of the ball screw will be more and more serious. To ensure that we have high-speed machine tools with higher precision and reliability, we need a brand new compensation system to offset thermal elongation. This paper first researches different temperature compensation systems of current machine tools, both passive and active, then compares the advantages and disadvantages of each system, and illustrates more economic, practical and competitive methods using the OMP-60 workpiece measurement system, which has been widely used in the field. With its high-precision sensors and instant on-line measurements, we can control the changes in temperature of the ball screws as well as enhance the machine's precision. Our main purpose is to help high-speed machine tool makers develop highly-precise products and create higher value added. Keywords: Hollow screw, Temperature compensation, Thermal elongation of the ball screw, OMP-60.

碩士
國立臺北科技大學
冷凍空調工程系所
102
The position error of a feed drive system was primarily caused by thermal deformation of a ball screw shaft. A high-speed ball screw system can generate massive heat after long-term operations with greater thermal expansion produced, and thereby unfavorably impact the positioning accuracy of the feed drive mechanism. In this study, we applied the computational approach using the finite element method (FEM) to simulate the thermal expansion process for estimating the deformation of the ball screw system. In the model, the deformation of the ball screw shaft was modeled by a linear elasticity manner given the assumption that the material was elastic, homogeneous, and isotropic. To emulate the reciprocating movements of the nut at the speeds of 20, 40 and 60 m/min corresponding to the screw shaft, we also utilized a three-dimensional unsteady heat conduction equation to determine the steady-state and transient temperature distributions, as well as temperature rises for calculating the thermal deformations of ball screws under operating situations. The analysis adopted the multi-zone heat loads to treat the heat generation sources from the frictions between the nut, bearings and the ball screw shaft. The predictions were compared with the experimental measurement for code validation. The simulated results showed that the countermeasures must be taken to thermally compensate great deterioration of the positioning accuracy due to vast heat production at high rotating speeds of shaft for a ball screw system.

碩士
國立虎尾科技大學
機械與機電工程研究所
100
Ball screw is a kind of accuracy linear transmission component. But with high rotational speed will cause more thermal displacement effects than low rotational speed. It produces different degrees of thermal expansion and a principal affecting reason of the positioning errors. A Finite element method (FEM) is used to construct a thermal analyzing model of nuts under frictional heating effects. The heat source model used ball screw kinematics to calculate a range of contact angle and average heat flux, the ball contact angle is considered as a normal distribution conditions. Boundary conditions of the analysis model have considered reciprocation by air convection effect. Thermal deformation analysis of the screw and nut were considered with internal contact geometry and temperature rise thermal effects, respectively. In the experiments, In-situ testing is held in hatchback machine of a ball screw system. This work puts the thermal couples inside the nut in order to instantaneously measure the variation of temperature, then it is can be used in the comparing with the simulation and experiment. Finally, results from experiment and simulation were confirmed for verification. Using the proposed model incorporating thermal is placement is easy applied in analysis of temperature rise control system.

碩士
國立虎尾科技大學
動力機械工程系機械與機電工程碩士班
104
The ball screw is a transmission element of high precision; however, the transmission element is displaced within the process because it causes wear and frictional heat between the ball and the orbital plane. Still, it also influences the platform’s transmission accuracy and stability. According to the kinematics of the ball screw, this research calculates the normal force, friction coefficient, and sliding velocity of the ball, the nut, and the screw. And consider the effect when the ball screw drive in the accelerate, isokinetic, and decelerate, to calculated the average heat flux of ball with contact surfaces on the track. Then, calculated the heat distribution rate between the ball, the nut, and the screw with the concept of heat resistance. Next, analyzed with Finite element method (FEM) of the total heat flux on the screw. Finally, set up the heat transfer boundary conditions. Both the change of temperature and the displacement of the screw are supported with each other. Therefore, it explores that the change of the temperature when preload appears within the process. And change to a different design parameters, include the radius of curvature and the contact angle,to analysis of screw temperature and deformation, than were made to the direction of the ball screw geometry. 　　The results show that, the preload will affect the overall temperature of the screw, and with the decline in preload, the heat flux by the screw groove surface can be decreased, resulting in temperature and deformation decreased, and affecting the accuracy of the positioning. In terms of temperature and experimental comparison error is only less than 8%, and the deformation is less than 15% by the thermal analysis model, this range has met our expectations, and explore the screw temperature and deformation with different design parameters of this model, can be found the contact angle increases to temperature decreases after the initial contact angle of 45˚, the overall temperature of screw is the lowest when 50˚.

碩士
國立彰化師範大學
電機工程學系
96
As the industrial production cost has soared continuously, the speed of machining becomes the most important index to match the market demand. This study discusses the movement conditions and stability of the design which raises the speed of axis movement from the construction in high speed machines. When the ball screws of feeding systems in high speed vertical machine center is turning, it causes the problem of thermal expansion due to high speed of friction, match up precision and parallel degree of assembling between screw and nut. The thermal expansion influences directly the accuracy and quality of machining. The result causes the shortening of machine’s life time. It is so called thermal displacement. Moreover, there will be side effect for larger pretension value. To improve the effect and maintain the precision under high speed movement, a new technology is needed to mend the defect. The new system can reduce the value of thermal expansion. With the pretension of ball screw, there will be great improvement in machining ability of high speed CNC machine. It increases the accuracy, quality of the machining and the life of machine, leading industries of Taiwan tool machine to a higher level, entering a higher value addition market to ensure the operating niche for the company.

碩士
雲林科技大學
機械工程系碩士班
96
For the high-accuracy machine tool, the environment heat and the heat generating from inside of machine are the main factors to affect the accuracy in machine. To confirm the accuracy in machine, the study of thermal characteristics including heat source, heat dispersion and thermal deformation are necessary. The purpose of the research is to set up heat and thermal deformation measurement system within ball screw of high precision boring machine and study the measuring data. Develop heat and thermal deformation model using finite element method to analyze the error and accuracy influenced by heat dispersion from ball screw of machine. Finally, Find the way to improve thermal deformation of ball screw.

碩士
國立中興大學
機械工程學系所
96
Due to the friction among nut, ball, screw, and bearing, and the heat generated by the servomotor, there will have heat accumulation on the ball screw and bearing. These heat accumulations will cause the problems of thermal temperature rising, thermal stress, and thermal deformation. To solve theoretical values of these thermal effects, the moving conditions of the ball screw is studied in the first beginning on this thesis. The friction torsions of the ball screw and bearing are then discussed to determine the thermal power on the ball screw and bearing. The formula of thermal temperature between ball screw and bearing is then established through thermal generation, thermal convection, 1-D thermal resistance, coefficient of general thermal convection, heat dissipation of fin. And finally, the equation of the thermal stress and thermal deformation for the ball screw is formulated through thermal expansion and static stress strain relationship. In this study, finite element analysis (FEA) is used to simulate the thermal temperature rising. From the simulation result, it is found that the temperature rising result by using coefficient of general thermal convection can be used for determining simulation of the thermal stress and thermal deformation of the ball screw. It is found that the simulation values are similar to the theoretical calculating values. The simulated thermal stress value is far less than the yield stress of the ball screw. Hence, the ball screw will not be destroyed under repetitive thermal expansion and contraction.

碩士
國立虎尾科技大學
機械與機電工程研究所
99
The thermal deformation effect is brought by the heat which is produced by the nut ball internal friction that is discussed in this research. The different pretension and whether the oil cooling in the screw conditioned the thermal deformation effect that is further discussed. These are used to investigate the internal stress and precise localization situation and to analyze the strain of screw surface and the stressed situation on ball screw and track to establish the real-time strain system. The system measures and observes different pretension to establish of the real-time strain measuring system. The system measures and observes different pretension to make the net surface strain have different changes. Simultaneously, the temperature is calculated by the elongation theory, also optical ruler is tested reality to monitor the range of displacement changes of the precise localization and to reappear situation. According the research, there are several results that assists to achieve the target that is high-speed ball screw precision positioning. First of all, the ball screw precision positioning establishes the finite element analysis that better than the traditional thermal expansion formula. Secondly, because of the nut hotter than the ball screw, therefore, the ball screw improves the precision positioning when the nut becomes the thermal expansion the oil cooling in the screw reduces the changes of the amount of positioning error. This is proved in the research of the precision position, the oil cooling in the screw and the different pretensions. Lastly, the pretension reduces the preload; inhibits the influence of the thermal deformation and reduces the screw deflection

碩士
國立雲林科技大學
機械工程系碩士班
97
In order to improve the efficiency of machine tools, the development of machine tools is toward high speed and high accuracy. To meet this trend, the speed and feed rate of spindle are increased. The high speed causes higher deformation, which affects the accuracy of machine tools. To maintain the accuracy of machine tools, the effects of environment temperature, heat sources, and heat transfer mechanisms on machine tools must be studied. In this study, the thermal deformation of two key components of machine tools: spindle and ball screw are studied. In the first part, finite element software ANSYS is used to perform the thermal and structural analysis of spindle under the friction heat generated by bearings. The simulated results of temperature distribution and axial deformation are verified by experimental measurements. In the second part, the thermal and structural analysis of ball screw are carried out by ANSYS. The effects of moving speed of sleeve on temperature distribution and deformation of ball screw are also discussed.

碩士
國立虎尾科技大學
機械與機電工程研究所
101
Ball screw is a kind of accurate actuation component, but with the applications of ball screw in a high speed and higher axial load conditions, components of a high performance ball screw generate friction heat and cause the variation of transmission properties. The topic is become more important and worth to exploring. Friction heat causes the thermal expansion makes the thermal expansion and affect ball tracks changes their size in circumstances. Therefore, thermal displacement occurring at the screw itself will affect precision transmission performance and positioning accuracy greatly. For ensuring the precision of the stable on a tool machine, the various of ambient temperature, heat generated by heat source of machine table, cooling design and thermal displacement researches are needed in order to dominated its basic features. Kinematical analysis of ball screw and Finite element analysis were used in the study of thermal expansion and thermal distribution after heat is occurred in nut. Then by experimental measurements of temperature and surface strain to compare the validation and use many different sensors to measure signal of transmission performance for impacting analysis. Transmission signals include the screw planning in different experimental conditions as well as under discussion of transmission torque, screw shaft deformation and rigidity of the machine. Results of this study also discusses the main source of heat for the machine between the ball and the nut frictional heat, and heat of friction is caused by the temperature rise associated with positioning screw thermal expansion becomes large and the transmission torque of the main factors, how to effectively reduce the temperature rise in the future to avoid machine design, calibration and positioning will be important to investigate the factor.

碩士
國立雲林科技大學
機械工程系碩士班
99
In recent years, the development of machine tools is toward high speed, high precision, and high accuracy. To achieve this trend, the feed rate mechanism is the key components. The machine tool feed system is mainly composed of servo motors, ball screw, and the linear slide. The ball screw has the backlash problem. The preloading on the screw increases the rigidity and reduces the backlash. In fast moving, the preloading leads to temperature rising, also causes thermal deformation. It affects the positioning accuracy of the main machine. The first part of this study is to use finite element software to simulate the temperature rising and thermal deformation of a ball screw under different preloads and feed rates. The simulated results are compared with measurements to verify the finite element model. The manufacturing processes have moved from micron level to nano level. The optical scale can no more used as a positioning tool. Most industries have adopted the laser interferometer as a new positioning tool. The accuracy of the laser interferometer is affected by the environment temperature. The second part of this study is to use CFD software CFX to simulate the temperature distribution under natural convection of a heated plate. Then the index of refraction of air along the path of laser light is calculated based on the temperature results. The relative position of laser light is affected by the index of refraction. The positioning error along the path of light of the laser interferometer is estimated by the variation of index of refraction of air along the path of light.

碩士
國立臺灣科技大學
機械工程系
106
AZ91 is the common magnesium alloy in industry. WZ73 become a new type of magnesium alloy material due to LPSO phase. As the demand for magnesium alloys grows year by year, the amount increase of magnesium alloys scrap will be expected. The scrap recovery problem can be solved if the scrap waste can be effectively utilized. In this study, swarf of AZ91 and WZ73 alloys were used to investigate the effects of processes, which were processed by thermal hydrogen processing, high energy ball milling, ball milling and thermal hydrogen combined processing, and the powder molded by hot pressing. The effect of the alloys swarf refining, microstructure and mechanical properties of hot pressing are discussed. The results show the average particle size of AZ91 swarf increased from 146.5 μm to 237.6 μm due to sintering effect in thermal hydrogenation processing, and the phases can recombine after thermal hydrogen processing. The average particle size of WZ73 swarf reduced from 144.8 μm to 129.0 μm, LPSO phase in WZ73 swarf was decomposed after thermal hydrogen processing whereas the YH2 phase formed, resulting in hydrogen cannot be desorbed. After ball-milled for 40 hours, AZ91 and WZ73 average particle size reduced to 21.5 μm and 19.8 μm, average grain size reduced to 22.4 nm and 22.6 nm, both the average size of particle and grain reduced by high energy ball milling. LPSO phase in WZ73 swarf was decomposed during the process of ball milling; where bismuth and zinc are segregated into grain boundary in the substrate. The phases in AZ91 can recombine after thermal hydrogen processing and ball milling, but LPSO phase in WZ73 can’t recombine after thermal hydrogen processing and ball milling. After ball-milled for 40 hours, the particle and grain size of AZ91 and WZ73 powder were similar, but AZ91 hot-pressed specimen strength was higher than WZ73 hot-pressed specimen, because LPSO phase in WZ73 decomposed after ball milling and AZ91 second phase Mg17Al12 was still in. After ball-milled for 40 hours, AZ91 and WZ73 powder because of small particle size, the hot-pressed at 200 °C has the best hardness of about 184.1 HV and 166.1 HV. After ball-milled for 40 hours and under thermal hydrogen processing, AZ91 powder hot-pressed specimen has higher compressive strength than hot-pressed specimen of ball-milled powder and a maximum compressive strength of 541.9 MPa, due to the dispersion of a large amount of Mg17Al12 phase by HDDR process. After ball-milled for 40 hours and under thermal hydrogen process, WZ73 powder hot-pressed specimen did not have higher compressive strength than hot-pressed specimen of ball-milled powder, due to the dispersion of a large amount of YH2 phase but less Mg24Y5 phase. Because the different of dispersed phase, AZ91’s data higher than WZ73’s. Thermal hydrogen processing provides the same effect as annealing, so the compression strain of hot-pressed specimen was enhanced.