ô Dalam tugasan kali ini,para pelajar telah diminta untuk menghuraikan tentang prosesproses membuat programming CNC-Mesin.Proses pemprograman adalah proses berkelompok iaitu program dibuat sekali melalui suatu kitaran yang boleh diulangi dalam kadar yang banyak mengikut kuantiti yang diperlukan. ô Program yang dibina akan menggunakan M code dan G code. ô etika berada pada posisi bersedia paksi X,Y dan Z berada pada kedudukan O pada mesin. ô erdapat dua jenis system koordinat iaitu system mutlak(G90) dan system monokok(G91). ô NC controler merupakan bahagian yang mengawal semua fungsi bahagian mesin.
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Setiap pengajaran dan pembelajaran yang diajar kepada pelajar oleh pensyarah mempunyai tujuan/objektif yang tersendiri. Oleh itu terdapat beberapa objektif utama diajar cara penggunaannya kepada pelajar antaranya ialah :
ô Supaya pelajar mengetahui apa itu G-code dan cara menukarkan gambarajah yang berskala kepada G-code. ô Dapat memahirkan menggunakan pengaturcaraan M- code. ô Melahirkan pelajar yang mahir dalam penggunaan mesin cnc milling. ô Supaya pelajar tahu jenis-jenis dan saiz mata alat yang patut digunakan di dalam mesin milling bagi mendapatkan hasil kerja yang terbaik. ô Supaya pelajar mengetahui cara menukar mata alat di dalam mesin cnc milling. ô Pelajar dapat mengetahui bagaimana mesin cnc milling beroperasi.
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Digunakan untuk memotong objek mengikut g-code yang telah diprogramkan.
Mata alat digunakan untuk memotong objek mengikut saiz yang telah ditetapkan. r
Pembuka ini digunakan untuk mengetatkan dan melonggarkan ikatan pada objek.
Berus ini dgunakan bagi membersihkan lebihan objek yang telah dipotong. ]
?angkah kerja melakukan simulasi (EXC? WIN 7) 1. 2. 3. 4.
Pilih software (EXC? WIN 7) ekan : Ê Pilih : New Project aip tajuk projek - Nama Projek -
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V. Pilih : p w. aip program baru untuk projek baru sehingga selesai. 7. p(Gunakan nombor program yang sama : o0007) 8. ekan : 9. Pilih : 10.Pilih : 11.ekan : ? 12.Pilih mata alat yang paling sesuai ( ) 13.ekan Ú 14.ekan : 1V.ekan : 1w.ekan : 17.ekan : º 18.Pilih : º 19.Masukkan saiz panjang, lebar dan tinggi yang baru. 20.ekan : 21.emudian tekan : Ô Ê 22.Setelah itu tekan : 23.Pilih : 24.Pilih : ÿ untuk melihat hasil kerja
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?angkah kerja pemotongan menggunakan mesin : 1. Segala peralatan seperti mata alat, bahan kerja dan peralatan lain disediakan. 2. Suis utama bekalan kuasa dihidupkan. 3. Suis bekalan pemampat yang menyediakan kuasa angin tambahan dihidupkan untuk menggerakkan mesin sebagai contoh untuk penukaran mata alat. 4. Suis utama di mesin dihidupkan dan tekan µNC¶ panel. unggu sehingga monitor memaparkan fungsi kawalannya. V. µEmergency button¶ ditarik dan butang µPower ON¶ ditekan. w. Skrin akan memaparkan µMachine Not Reference¶ . button µJOG¶, µREF RE RN¶ dan µCYC?E SR¶ ditekan. 7. Paparan µSpindle Warm p¶ akan keluar. Butang µREF RE RN dan SPIND?E %$¶ ditekan serentak. 8. Program dimasukkan mdengan menekan butang-butang mengikut pengaturcaraan yang disediakan. 9. Masukkan program daripada computer dengan memasukkan nama program baru EDI ± PROG ± DIR ± masukkan nombor program O0007. 10.emudian, tekan + pada skrin ± tekan RED ± EXEC. 11.Pada computer pula, pastikan berada di bahagian EDI ± D RNSFER ± pilih µFile Name¶ program yang hendak dimasukkan dan SR ditekan. 12. Bagi seting bahan kerja, suis µHND?E¶ ditekan untuk menggunakan µHND WHEE?¶ bagi menggerakkan secara manual. 13.edudukan koordinat paksi ±Z dilaraskan dengan mendekati mata alat pada permukaan bahan kerja. Butang µWORSHIF¶ ditekan. Bacaan mesin iaitu Z- 320.80V diambil dan jejari mata alat sebanyak 2.000 dimasukkan. 14.edudukan koordinat paksi-X dan paksi ±Y dilaraskan dengan mendekati mata alat pada bahan kerja. Butang µWORSHIF¶ ditekan. Bacaan tersebut perlulah ditolakkan dengan 2.000 dan kemudian masukkan nilai pada ruang GV4 iaitu X -442.wVw kepada -444.wVw dan Y- 321.330 kepada -323.330. 1V.?angkah 11 bagi paksi ±Y diulangi 1w. ntuk melihat kedudukan mata alat, bawa mata alat pada koordinat X, Y dan Z yang dimasukkan ke dalam jadual mesin dengan menggunakan µHand Wheel¶. 17.Setelah yakin kedudukan ORIGIN maka butang µPOS¶, Rel ditekan dan tekan X. X akan berkelip-kelip dan ORIGIN ditekan. 18.?angkah 14 diulangi untuk Y dan Z. 19.µPROG¶ ditekan untuk memaparkan semula program yang ditaip. 20.µ O¶ dan µCYC?E SR¶ ditekan. 21.Pemotongan dilakukan. 22.Mesin ditutup setelah benda kerja dikeluarkan dan mesin dibersihkan. 23.µEMERGENCY SOP¶ dan suis utama mesin ditekan untuk menutup mesin.
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Di dalam bengkel,keselamatan amat diutamakan supaya tidak berlaku perkara-perkara yang tidak diingini. ntara langkah-langkah keselamatan ialah : ô Pelajar perlu memakai kasut bengkel yang telah ditetapkan. ô Pelajar perlu memakai baju bengkel yang telah disediakan oleh pihak politeknik. ô Bagi pelajar perempuan,tudung perlu dimasukkan ke dalam baju bengkel supaya tidak tergantung dan membahayakan diri ketika melakukan kerja. ô Sarung tangan perlu dipakai ketika memegang objek sebelum dan selepas okerja dijalankan supaya serpihan objek tidak melukakan tangan. ô Jika kad matrik tergantung dan membahayakan,pelajar perlu memohon kepada pesyarah untuk menyimpan kad matrik di dalam poket.
Dalam menjalankan amali yang telah dberikan,terdapat beberapa masalah yang kumpulan kami hadapi. ntaranya ialah :
ô ami terpaksa memikirkan gambarajah apa yang kami perlu ambil bagi menyempurnakan tugasan yang telah diberikan. ô ami juga menghadapi kesukaran untuk menukarkan gambarajah tersebut kepada betuk G-code. ô Selain itu,masa yang dibeikan kepada kami untuk menyiapkan laporan terlalu singkat sehinggakan kami tidak dapat menyiapkannya dalam masa yang telah ditetapkan. ô Semasa proses pengajaran,kami juga menghadapi masalah kurang memahami apa yang diajar tapi kerana penerangan dari pensyarah,kami dapat memahaminya.
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Daripada perbincangan kami terdapat beberapa cadangan amali/bengkel pada masa hadapan supaya memberikan keselesaan pada pelajar yang akan datang. ntaranya ialah :
ô enaga pengajar memberikan satu gambarajah kepada kami untuk kami tukarkan kepada G-code sehingga mendapatkan hasil kerja di atas objek yang digunakan. ô Jika mempunyai kos yang berlebihan,diharapkan pihak yang bertanggungjawab dapat menambahkan bilangan mesin cnc milling. ô Masa waktu pembelajaran dipendekkan kerana pelajar akan cepat mengantuk dengan keadaan bengkel yang terlalu selesa. ô Pelajar juga harus diberikan ruang untuk berehat dan bersarapan sebentar supaya mempunyai tenaga untuk belajar dengan lebih tekun. ô mali yang diberikan harus melibatkan semua pelajar untuk member peluang kepada pelajar itu sendiri belajar dan mengajar.
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esimpulannya segala objektif yang ingin dicapai telah berjaya dilaksanakan. Segala tunjuk ajar yang diberikan oleh tenaga pengajar kepada kami telah kami manfaatkan sebaik mungkin. ami telah berjaya menggunakan mesin cnc milling dengan mahir dan mengetahui cara memasukkan program dan menjalankan mesin tanpa ada sebarang masalah yang dihadapi.selain itu,kami juga mengetahui telah menukarkan program kepada bentuk G-code dan mendapatkan hasil seperti gambarajah di atas.segala yang diajarkan kepada kami memang benar-benar berguna untuk kami manfaatkan apabila melangkah ke alam pekerjaan nanti.
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Example of a CNC vertical milling center milling machine is a machine tool used for the complex shaping of metal and other solid materials. Its basic form is that of a rotating cutter or end mill which rotates about the spindle axis (similar to a drill), and a movable table to which the work piece is affixed. hat is to say, the cutting tool generally remains stationary (except for its rotation) while the work piece moves to accomplish the cutting action. Milling machines may be operated manually or under computer numerical control (see CNC V?). Milling machines can perform a vast number of complex operations, such as slot cutting, planning, drilling, rebating, routing, etc. Cutting fluid is often pumped to the cutting site to cool and lubricate the cut, and to sluice away the resulting swarf.
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miniature hobbyist mill plainly showing the basic parts of a mill. c #&!""!#$%!# '
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here are two main types of mill: the vertical mill and the horizontal mill. In the vertical mill the spindle axis is vertically oriented. Milling cutters are held in the spindle and rotate on its axis. he spindle can generally be extended (or the table can be raised/lowered, giving the same effect), allowing plunge cuts and drilling. here are two subcategories of vertical mills: the bed mill and the turret mill. urret mills, like the ubiquitous Bridgeport, are generally smaller than bed mills, and are considered by some to be more versatile. In a turret mill the spindle remains stationary during cutting operations and the table is moved both perpendicular to and parallel to the spindle axis to accomplish cutting. In the bed mill, however, the table moves only perpendicular to the spindle's axis, while the spindle itself moves parallel to its own axis. lso of note is a lighter machine, called a mill-drill. It is quite popular with hobbyists, due to its small size and lower price. hese are frequently of lower quality than other types of machines, however. horizontal mill has the same sort of A± table, but the cutters are mounted on a horizontal arbor across the table. majority of horizontal mills also feature a +1V/-1V degree rotary table that allows milling at shallow angles. While end mills and the other types of tools available to a vertical mill may be used in a horizontal mill, their real advantage lies in arbor-mounted cutters, called side and face mills, which have a cross section rather like a circular saw, but are generally wider and smaller in diameter. Because the cutters have good support from the arbor, quite heavy cuts can be taken, enabling rapid material removal rates. hese are used to mill grooves and slots. Plain mills are used to shape flat surfaces. Several cutters may be ganged together on the arbor to mill a complex shape of slots and planes. Special cutters can also cut grooves, bevels, radii, or indeed any section desired. hese specialty cutters tend to be expensive. Simplex mills have one spindle, and duplex mills have two. It is also easier to cut gears on a horizontal mill.
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more complex form of the milling machine is the milling machine, in which the rotating cutter can be oriented vertically or horizontally, increasing the flexibility of the machine tool. he table of the universal machine can be swiveled through a small angle (up to about 1V degrees), enabling the axis of the spindle to coincide with the axis of a helix to be milled with the use of a gear driven indexing head. Milling machine variants º are very basic hobbyist bench-mounted milling machines that feature a head riding up and down on a column or box way. are more commonly referred to as bridgeport-type milling machines. he spindle can be aligned in many different positions for a very versatile, if somewhat less rigid machine. are larger, industrial production mills. hey feature a knee and fixed spindle head that is only mobile vertically. hey are typically much more powerful than a turret mill, featuring a separate hydraulic motor for integral hydraulic power feeds in all directions, and a twenty to fifty horsepower motor. Backlash eliminators are almost standard equipment. hey use large NMB 40 or V0 tooling. he tables on C-frame mills are usually 18" by w8" or larger, to allow multiple parts to be machined at the same time. refers to any milling machine that has a vertically adjustable table. º refers to any milling machine where the spindle is on a that moves up and down to move the cutter into the work. hese are generally more rigid than a knee mill. refers to a mill that has a swiveling cutting head mounted on a sliding ram. he spindle can be oriented either vertically or horizontally, or anywhere in between. Van Norman specialized in ram type mills through most of the 20th century, but since the advent of CNC machines ram type mills are no longer made. cw
Ñ are vertical mills that are built to bore holes, and very light slot or face milling. hey are typically bed mills with a long spindle throw. he beds are more accurate, and the handwheels are graduated down to .0001" for precise hole placement. å are large, accurate bed horizontal mills that incorporate many features from various machine tools. hey are predominantly used to create large manufacturing jigs, or to modify large, high precision parts. hey have a spindle stroke of several (usually between four and six) feet, and many are equipped with a tailstock to perform very long boring operations without losing accuracy as the bore increases in depth. typical bed would have X and Y travel, and be between three and four feet square with a rotary table or a larger rectangle without said table. he pendant usually has between four and eight feet in vertical movement. Some mills have a large (30" or more) integral facing head. Right angle rotary tables and vertical milling attachments are available to further increase productivity.
have a row of rotary tables, and a horizontal pendant spindle mounted on a set of
tracks that runs parallel to the table row. hese mills have predominantly been converted to CNC, but some can still be found (if one can even find a used machine available) under manual control. he spindle carriage moves to each individual table, performs the machining operations, and moves to the next table while the previous table is being set up for the next operation. nlike any other kind of mill, floor mills have floor units that are entirely movable. crane will drop massive rotary tables , X-Y tables , and the like into position for machining, allowing the largest and most complex custom milling operations to take place. It has the spindle mounted in a structure where 2 or 3 combined travels can be made depending if the work table is static or cross moved; he choice for one type or other in this case depends mostly on the part to be machined i.e. on its weight. herefore the "ap" or "stepdown" needed on the average work done, should be considered, to watch for the torque on the moving axis
Computer numerical control
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hin wall milling of aluminum using a water based coolant on the milling cutter Most CNC milling machines or machining centers are computer controlled vertical mills with the ability to move the spindle vertically along the Z-axis. his extra degree of freedom permits their use in diesinking, engraving applications, and 2.VD surfaces such as relief sculptures. When combined with the use of conical tools or a ball nose cutter, it also significantly improves milling precision without impacting speed, providing a cost-efficient alternative to most flat-surface hand-engraving work.
Five-axis machining center with rotating table and computer interface CNC machines can exist in virtually any of the forms of manual machinery, like horizontal mills. he most advanced CNC milling-machines, the V-axis machines, add two more axes in addition to the three normal axes (XYZ). Horizontal milling machines also have a C or Q axis, allowing the horizontally mounted workpiece to be rotated, essentially allowing asymmetric and eccentric turning. he fifth axis(B-xis) controls the tilt of the tool itself. When all of these axes are used in conjunction with each other, extremely complicated geometries, even organic geometries such as a human head can be made with relative ease with these machines. But the skill to program such geometries is beyond that of most humans. herefore, V-axis milling machines are practically always programmed with CM. With the declining price of computers, free operating systems such as ?inux, and open source CNC software, the entry price of CNC machines has plummeted. For example, Sherline, Prazi, and others make desktop CNC milling machines that are affordable by hobbyists.
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High speed steel with cobalt endmills used for cutting operations in a milling machine.
Milling machine tooling here is some degree of standardization of the tooling used with CNC Milling Machines and to a much lesser degree with manual milling machines. CNC Milling machines will nearly always use S (or ISO), C, B or HS tooling. S tooling is the most common in Europe, while C tooling, sometimes called V-Flange ooling, is the oldest variation and is probably still the most common in the S. C tooling was invented by Caterpillar Inc. of Peoria, Illinois in order to standardize the tooling used on their machinery. C tooling comes in a range of sizes designated as C-30, C-40, C-V0, etc. he number refers to the ssociation for Manufacturing echnology (formerly the National Machine ool Builders ssociation (NMB)) aper size of the tool.
C-40 oolholder n improvement on C ooling is B ooling, which looks very similar and can easily be confused with C tooling. ?ike C ooling, B ooling comes in a range of sizes and uses the same NMB body taper. However, B tooling is symmetrical about the spindle axis, which C tooling is not. his gives B tooling greater stability and balance at high speeds. One other subtle difference between these two toolholders is the thread used to hold the pull stud. C ooling is all Imperial thread and B ooling is all Metric thread. Note that this affects the pull stud only, it does not affect the tool that they can hold, both types of tooling are sold to accept both Imperial and metric sized tools.
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S and HS tooling, sometimes called "Hollow Shank ooling", is much more common in Europe where it was invented than it is in the nited States. It is claimed that HS tooling is even better than B ooling at high speeds. he holding mechanism for HS tooling is placed within the (hollow) body of the tool and, as spindle speed increases, it expands, gripping the tool more tightly with increasing spindle speed. here is no pull stud with this type of tooling. he situation is quite different for manual milling machines ² there is little standardization. Newer and larger manual machines usually use NMB tooling. his tooling is somewhat similar to C tooling but requires a drawbar within the milling machine. Furthermore, there are a number of variations with NMB tooling that make interchangeability troublesome.
Boring head on Morse aper Shank wo other tool holding systems for manual machines are worthy of note: hey are the R8 collet and the Morse aper #2 collet. Bridgeport Machines of Bridgeport, Connecticut so dominated the milling machine market for such a long time that their machine "he Bridgeport" is virtually synonymous with "Manual milling machine." he bulk of the machines that Bridgeport made from about 19wV onward used an R8 collet system. Prior to that, the bulk of the machines used a Morse aper #2 collet system.
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