intro.pptx
- 1. FUNDAMENTAL OF MACHINE TOOLS Machine tools power operated machine Expend energy to cut metal Metal removed from blank in form of chips to develop required product Required finish and accuracy of the part is to be maintained Uses cutting tool Non portable Example-lathe, milling,broaching and so many Operations- Hold the blank Hold cutting tools Dofferent types of motion-linear, rotary, combination or intermittent as nedded for different parts Input-information of job shape,size -work shape.size, material - energy,machine tool information Output-required shap. Size accuracy -finish and integrity of surface -rate of production, mfg cost/piece input output machine tool operator feed back to operator Man machine system
- 2. Lathe Machine Drilling Machine
- 3. Classification Based on field of application i. General purpose- Highly flexible, wide range of work-piece Variety and material, cost effective job Production. Ex-plain turning lathe, turret lathe, milling machine, grinding machine etc. ii. Production purpose- Less flexible, work variety and material limited, cost effective batch and mass Production. High power and rigid. ex- multi tool lathe, plunge cut grinder etc. iii. Specialized – same shape but different size product. Readily can be switched over from one job to other. Ex- iv. Single purpose –specialized for a definite machining operation. Ex. Thread cutter, gear hobber etc. v. Special machine tool—tool grinder, threading by die tap etc. Based on configuration- horizontal, vertical, inclined Based on primary machining operation- turning, milling, grinding, combination machine tool Based on nature of cutting motion- Rotating tool/reciprocating tool According to accuracy– normal accuracy-majority of components Higher accuracy-critical parts requiring assembly and alignments Precision- more stringent accuracy and narrow tolerance Based on environment- Heavy duty->10kw, continuous running Medium duty-3-10kw, medium load Small duty- <3KW, small load and minimum time of running Based on degree of automation- Manual-control Semi automated- automated-
- 4. Major components of machine tools Components for holding tool and workpiece Prime mover to provide power Kinematic chain for transmission and transformation of power Structural body sufficient to support dead and live load within specified limit Proper control and automation systems Specification of machine tools It is the parameters to express the functional requirements of the machine Tools. generally they are • Size limit of the work • Maximum and rated power • Spindle speed-range, no of divisions • Feed ranges • Floor space , weight etc. • So many others Types of motion in machining (i) primary motion—it serve the purpose of removing metal. It is two types (a) principal/ cutting motion- depends on optimum cutting speed for tool work-piece combination and nature of machining. It may be rotary, linear or combination of both (b) feed motion-depends on required finish of the product. It may be continuous, intermittent, compound (ii) auxiliary motion- it help to accelerate other processes involved in production apart actual machining. This motion may be hand driven or automated. Ex- changing of speed and feed, clamping and unloading of work in the machine tool etc.
- 5. Performance criteria of machine tools Safety Ease of operation-less fatigue for operation, loading, unloading and bringing tool and workpiece in engagement should be easier by automation or quick acting clamp etc. Production accuracy-geometric, locational and dimensional accuracy with surface integrity as per requirement. Possible if machine tools is designed with sufficient stiffness and alignment and manufacturing accuracy of components. Production capacity-max. no. work-piece per unit time would be as per required. Reliability and maintainability- Ease of maintenance Compactness-should be high, fixed and operating cost should be as low as possible. Cost effectiveness of machine tools 1 2 3 Cost Of Prdn. Rate of production 1.General purpose 2. NC Mahines 3.Special purpose machine