Dec 11, 2007 please help me to calculate theoratical machining cycle time for the below mentioned operations. Build your own complete process plan and generate detailed cost estimates. It is used by erp and mes systems for scheduling, purchasing and production costing. Regarding tool life, a simple detail relating to twocut hobbing processes has also been realized. Estimating hob times julyaugust 1989 gear technology. Be assured that change gear sets will be the best ratio match available from your inventory and will fit at the machine. This is achieved by shifting the hob in axial direction by using following calculations, where micro shifting is not available on hobbing machine. Additionally, the work table is designed to allow great accessibility to the hob head. The tnc 640 will take care of the remaining calculations, particularly for dynamic motion control in doublespindle operation. Gear cutting and grinding machines and precision cutting.
Mar 01, 2014 the software can analyze the influence of different cutting tool geometries and process parameters on chip formation, gear quality, collision situation and cycle time. Gcp2 calculates for both normal and transverse planes. It hase everything from gear formulae, thread calcs etc to calculations for wire size including the involute tables you need when calculating size over oddball measuring wires. In a nontopping tool, there has to be a certain amount of clearance between the tool and the gear tip circle, which the software checks. Whether you are studying machining or planning to get all parameters just right for your next cut, the machining calculator app from sandvik coromant will provide the calculations needed based on the parameters you input. Hobbing is a continuous gear generation process widely used in the industry for high or low volume production of external cylindrical gears. You do need a lathe however, and a lot of builders who know how to use one can use the method described here. Gear hobbing cutting process simulation and tool wear prediction models gear hobbing is an ef. Gear hobbing, shaping and shaving a guide to cycle time estimating and process planning. Gear hobbing machine process overview gear hobbing. During the hobbing of some gears or splines, the cutter win not feed completely. With our direct drive cnc gear hobbing machine, the cycle times can be reduced by 3 to 4 times when compared with conventional machines. The gear face width isalso indicated on the part print as the width ofthe gear blank.
Pdf design of gear hobbing processes using simulations. A novel simulation code was developed aiming at the simulation of the gear hobbing process. Everyone involved in gear design and production will benefit from the practical guidelines in this book. Connecting cycle time to lean machine productivity. A guide to cycle time estimating and process planning endoy, robert on. The dry gear hobbing process allows machining of gears with a quality. Rigibore accepts no liability for the information provided on this page, select a tab below to begin. The makers of gear units have quite a choice of gear cutting and gear forming techniques at their disposal, including hobbing, shaping, grinding, broaching, milling and rolling. Simulate the machining process to verify tool paths before automatically generating a cnc program for your machine.
This software is enhanced to be capable of simulating the surface topography of the. The lmtfette twist free concept adds little to no extra cycle time to an existing twopass hobbing application. Gear hobbing cycle time calculator for ipad for ios free. Your problems are addressed in page 118 pf the 1961 edition. Chamfercut in addition, liebherr hobbing machines are available with a separate chamfercut unit for simultaneous. Software for the gear manufacturer gcp2 ash gear s own gear calculation software. The work table master gear diameter is more than 6 times larger than the max. The simulation results show that the hobbing process has a lot of excellent process characteristics, such as good adaptability, continuous cutting, no extra stroke, higher productivity. Pdf calculating the workpiece quality using a hobbing simulation. With high speed stroking, narrow width job can be finished in lesser time than by hobbing. Cutting machining time calculation cutting machining time inclusive of setting up the machine, getting the tools, study of drawing. By executing a penetration calculation, values such as. The first step of the calculation process is the calculation of the effective cutting hob teeth n for which the.
Calculating the workpiece quality using a hobbing simulation. A revolution in hobbing technologies gear solutions. Hobbing machines, multitask machines, 5axis machines. Machining calculator app calculating cut settings made easy. Due to these unique and complex kinematic conditions, a calculation based on analytic formulas of the maximum chip thickness is not possible. It should be noted that the calculation of gear load capacity by pitting resistance was sufficient in case of classical theory of fatiguelife. In order to evaluate chip thickness, calculate the maximum chip thickness hex to determine axial feed rate. Online calculation of change gears for machine tools. Hobbing isa continuous gear generation process widely used in the industry for. It will give him the application of the rules necessary to turn a gear blank in a table and to tromp the teeth on a milling machin. Total time weighted time total distance weighted distance by volume a c d e b f totals calculations weighted cycle time to common junction empty weighted cycle time to common junction loaded contractor licensee licensee representative weighted empty cycle time from common junction weighted loaded cycle time to common junction. Chamfering runs simultaneously if the cycle time is sufficient. Because gear calculations require many complex formulas related to strengths and sizes, traditional gear design.
In the lean model, cycle time improvements are driven by workers, based on their knowledge of the work and and minimizing nonvalue added work. When mor than one part isloaded per cycle, the total gear width must. Gear hobbing 1 free download as powerpoint presentation. For some gear forms, the work also requires the machine to have yaxis motion in addition to x and z.
In 8 and 9 the simulation software spartapro for the calculation of characteristic values for the gear hobbing process was introduced. Invite colleagues or customers to directly view your estimate. Gear machining is performed during the soft stage process, where the. This is an excellent explanation of gear hobbing process by two gear manufacturing experts well known for their expertise. Calculation and design, herringbone gearing, gear hobbing classic reprint by george w. Simulation software, proceedings of the world congress on. A guide to cycle time estimating and process planning. The hob generates a gear tooth profile by cutting several facets of each gear tooth profile through a synchronized rotation and feed of the work piece and cutter. The allowable errors and the minimum and maximum change. A novel gear hobbing simulation software nikolaos tapoglou, aristomenis antoniadis e. The root of the tooth can be chamfered without difficulty.
Comparison of chip formation in various cutting processes 2. Simulation analysis on hobbing process and heat treatment of. In the molding generating process of gear shaping fig. Just by eliminating scrap and return trips to the computer, cpchob will improve your productivity. The variant cutting contribution of each hob tooth to the gear.
Program skiving and hobbing operations klartextportal. Depending on the tooth size, gears and splines are hobbed in a single pass or in a twopass cycle consisting of. Machining operations cycle time mit opencourseware. Cadbased calculation of cutting force components in gear hobbing. Every production process is inevitably a compromise between ease of machining, good surface finish, profile accuracy, speed of output and economic production. Cutting times and disposable hobs an important part of overall hobbing cycle is taken up by the actual tooth cutting operation, that is the time that the hob is in contact with the workpiece. Cutting gears for reduction gearing on cfs is not an option for the home builder with limited facilities, but cutting worm wheels for fine focusing is. Max hex is calculated according to hoffmeisters equation.
Cadbased calculation of cutting force components in gear. Spreadsheet for gear hobbing louis belet sa cutting tools. Turning, milling, drilling, tapping and reaming all require complex calculations to achieve wanted results. The factors that contribute to reduced cutting time for both shanktype and boretype hobs include increasing feedrate and hob speed and the number of threads on the hob. Oct 10, 2012 primitive worm gear hobbing in a lathe. Jan 23, 2010 a very brief introduction of gear cutting and gear calculations this article will supply the beginner with sufficient information to enable him to understand gear, gear terms, types of gears and the rules used in making spur gears. Gear hobbing cutting process simulation and tool wear. Depending on the tooth size, gears and splines are hobbed in a single pass or in a twopass cycle consisting of a roughing cut followed by a finishing cut.
Please help me to calculate theoratical machining cycle time for the below mentioned operations. These results will need adjusting depending on specific machining conditions. A very brief introduction of gear cutting and gear calculations this article will supply the beginner with sufficient information to enable him to understand gear, gear terms, types of gears and the rules used in making spur gears. Tool life is limited by the heaviest cuts and thickest chips. Shaving i need variious calculations involed in determining the theoratical cycle time. Calculation and design, herringbone gearing, gear hobbing classic. It is also a critical part of the oee calculation use our oee calculator here. Most important part of hobbing operation is to use the optimal life of hob by uniformly distributing the wear amount. As tool designers try to optimize performance, they look to smaller diameter tools because smaller diameters allow for higher cutter speeds at given surface feet per minute. The results that take into account the new fatigue resistance level with precision of stress cycle factors are more real see table 2. Very high performance gear transmission module is composed of involute gears.
When setting up a hobbing operation, we must firstly select the type of cycle to use from the various options available. The software can analyze the influence of different cutting tool geometries and process parameters on chip formation, gear quality, collision situation and cycle time. Now, the total cost per gear can be calculated considering the bestsuited cutter size, the cost for a new cutter, and the cost for resharpening in combination with the expected. External involute gears can be manufactured with a series of methods of which gear hobbing is the most widely applied. This ratio creates a highly accurate hobbing process.
To perform hobbing on a turning center, the lathe requires a polygon option in its cnc. Characteristic values in gear hobbing gear hobbing is the main process for manufacturing cylindrical gears 3. Stateoftheart hobbing machines have the capability to vary cutting parameters between first and second cut so that a different formula is used to calculate cycle times for singlecut and doublecut hobbing. The time to complete a task or collection of tasks. Gears of diferential for additional rotation of the workpiece during manufacturing of helical gears for gear profile grinding machines, niles. The dry gear hobbing process allows machining of gears with a quality according to the din standard of up to it 5. The gear calculator is a comprehensive software which, after inputting various parameters related to gear calculations, computes online automatically gear sizes, strengths, working forces, tooth forms, backlash conversions, etc. For all the possible gear ratio in fractions of seconds calculate milling of gears with the gear hob, gear hobbing, pfauter. The cycle time formula is an essential manufacturing kpi to understand in manufacturing. Refer to it onthejob for tips on process selection process planning, cycle time formulas and calculations, speeds and feeds, and volume considerations.
Jun 11, 2014 difference between gear hobbing and gear shaping. Gear hobbing is not a form cutting process, such as gashing or milling where the cutter is a conjugate form of the gear tooth. Cycle time is the time between commencement and completion of a process, therefore, in a customer call centre, the cycle time for a customer phone call may be the time difference between answering the call and call completion. Want to learn more about the basics of metal cutting.
Changegears main window contains inputs to describe the gear geometry and cutting parameters. The desired process throughput is inverse takt time. All you need to do is specify the data for the gear geometry and the tools to be used. The teeth or splines of the gear are progressively cut into the material a flat, cylindrical piece of metal by a series of cuts made by a cutting tool called a hob. Just by eliminating scrap and return trips to the computer, cpc hob will improve your productivity. Refer to it onthejob for tips on process selection, process planning, cycle time formulas and calculations, speeds and feeds, and volume considerations. Design of gear hobbing processes using simulations and. Formulas for gear calculation external gears contents.
Acedes hobbing cycle time calculator acedes gear tools. Gear hobbing, shaping and shaving a guide to cycle time. Hobbing is the metalcutting operation that generates gear teeth using a specialized tool called a hob. Time min spur 1 spur 2 travel speed kmhr secondary a secondary b total time weighted time total distance weighted distance by volume a c d e b f totals calculations weighted cycle time to common junction empty weighted cycle time to common junction loaded contractor licensee licensee representative weighted empty cycle time from. Spreadsheet for gear hobbing louis belet sa cutting. The current method for this calculation is very complicated and time consuming. To reduce the computational time, a new calculation strategy has been developed. Just as cash flow is a direct measure of company financial performance, cycle time is a direct measure of process and equipment performance. The corrected profile is positive when the pitch line of the rack is above the cutting pitch circle of the gear. This is because of the generating nature of this particular cutting process. Estimating gear fatigue life gear solutions magazine. The work table is driven by cylindrical gears allowing 500 rpm table speed. Speeds and feeds calculated are for guide purposes only. Hob bing isa continuous gear generation process widely used in the industry for high or low volume production of external cylindrical gears.
A general rule of thumb is that climb hobbing yields better tool life, and. Time cycle will be 23 times of hobbing for wider gears. Hobbing feed during bobbing, the cutting tool can be fed in a manner similar to a milling machine. Jul 08, 2014 hobbing machines provide gear manufacturers a fast and accurate method for cutting parts. Fortunately, it is easy to calculate and understand. Homemade gear casting, method of homemade silicone duration. If applicable, the savings can be more than significant when considering the cost of machine tools, cutting tools, and labor eliminated. Included in the production programme are gear hobbing machines, gear shaping machines and generating and profile grindingmachines, all noted for their high degree of. Estimating hohhing times robert endoy ford new holland, inc. I hope this will be a great help for those who want to explore gear making processes. Relationship between the involute elements determination of base tooth thickness from a known thickness and viceversa. Cycle time improvements, such as that shown in step one, are easy for management to drive because machines are idle. By using this simulation program it is possible to reduce the costs and time effort of. Cutting machining time inclusive of setting up the machine, getting the tools, study of drawing.
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