Milling Machines
منتدى هندسة الإنتاج والتصميم الميكانيكى
بسم الله الرحمن الرحيم

أهلا وسهلاً بك زائرنا الكريم
نتمنى أن تقضوا معنا أفضل الأوقات
وتسعدونا بالأراء والمساهمات
إذا كنت أحد أعضائنا يرجى تسجيل الدخول
أو وإذا كانت هذة زيارتك الأولى للمنتدى فنتشرف بإنضمامك لأسرتنا
وهذا شرح لطريقة التسجيل فى المنتدى بالفيديو :
https://www.youtube.com/watch?v=aw8GR3QlY6M
وشرح لطريقة التنزيل من المنتدى بالفيديو:
https://www.youtube.com/watch?v=Lf2hNxCN1cw
https://www.youtube.com/watch?v=PRIGVoN7CPY
إذا واجهتك مشاكل فى التسجيل أو تفعيل حسابك
وإذا نسيت بيانات الدخول للمنتدى
يرجى مراسلتنا على البريد الإلكترونى التالى :

DEABS2010@YAHOO.COM



 
الرئيسيةالبوابةاليوميةس .و .جبحـثالتسجيلدخولحملة فيد واستفيدجروب المنتدى
شاطر | .
 

 Milling Machines

استعرض الموضوع السابق استعرض الموضوع التالي اذهب الى الأسفل 
كاتب الموضوعرسالة
Admin
مدير المنتدى
مدير المنتدى
avatar

عدد المساهمات : 14413
التقييم : 23257
تاريخ التسجيل : 01/07/2009
العمر : 29
الدولة : مصر
العمل : مدير منتدى هندسة الإنتاج والتصميم الميكانيكى
الجامعة : المنوفية

مُساهمةموضوع: Milling Machines    الجمعة 01 أكتوبر 2010, 8:02 pm


Introduction

A milling machine is a machine tool that cuts metal with a multiple-tooth cutting tool calleda milling cutter. The workpiece is fastened to the milling machine table and is fed againstthe revolving milling cutter. The milling cutters can have cutting teeth on the periphery or sidesor both. The cutting teeth can be straight or spiral.

Milling machines can be classified under three main headings:..

  1. General Purpose machines - these are mainly the column and knee type (horizontal & vertical machines)
  2. High Production types with fixed beds- (horizontal types)
  3. Special Purpose machines such as duplicating, profiling, rise and fall , rotary table ,planetary and double end types
Milling attachments can also be fitted to other machine tools including lathes planing machines and drill bench presses canbe used with milling cutters.

Additional Notes
Cutting Tool Materials... Cutting Tool Materials..
Cutting Fluids... Cutting Fluids..



Milling Cutters

There are a wide range of milling cutters as illustrated in BS 122-1. these include


  • Plain cutters ( most types have straight or helical teeth)
  • End mills (taper or parallel shank, slotting or shell)
  • Cylindrical side and face slotting,screw slotting
  • Single,double and equal angle cutters:
  • T-slot, convex, single and double corner rounding cutters
  • Metal slitting saws:
  • Hollow Mills
Typical Milling cutters


Tee Slot Milling Cutter


Shell End Mill


High Helix Cylinderical Cutter


Slotting Cutter


Relevant Standards

BS 122-1:1953..Milling cutters. Milling cutters
BS 122-4:1980..Milling cutters. Screwed shank end mills and slot drills
BS 122-5:1986..Milling cutters. Specification for mounting dimensions and accessories
BS 122-6:1995, ISO 240:1994..Milling cutters. Specification for dimensions for interchangeability of cutter arbors and cutter mandrels


Column and Knee Machine -Vertical Milling Machine

Vertical milling machines have their cutting tool spindles vertical and are characterised byby their heavy overarms which are integral with their columns. This provides rigid supportfor the spindle housing which is set at a fixed distance from from the column. The milling head can be adjusted vertically

The diagram below shows the primary controlled motions available with this type of milling machine.
Column and Knee Machine - Horizontal Milling Machine

This is the basic milling machine configuration. The workpiece can be fed in all three axes and is suitable for short production runs but it is not as rigid as a fixed bed machine and should not be used for heavy duty work. Because of the large number of controls it is relatively slow to operate.



Fixed Bed Milling Machines

Fixed bed or production type machines are designed for rapid metal removal requiring the minimumof operator involvement. On this type of machine the table is fixed permitting machine tablemovement in one horizontal direction only. the workpiece has to be fixed in one locationon the table and all vertical movements for feeds and lateral positioning are by moving the spindle in the spindle carrier mounted on the headstock. A plain machine has just one spindle and a duplex machine has two spindles. this type of machine can have one column or two columns providing more rigidity.


Horizontal Milling Feed Direction
The direction of feed in relation to the direction of cutter rotation is and important factorin horizontal milling. Conventional up milling requires that the workpiece is fedagainst the rotation of the cutter. In down milling the workpiece moves in the seam directionas the surface of the rotating cutter. The tow alternatives are shown in the figure below



In up milling the cutter tooth starts cutting into clean metal with zero chip thickness and ends with the maximum chip width and rought metal. The cutter stays sharp long and the motion of the feed compensates for wear or backlash in the feed system. The cutter tends to lift up the workpiece and high clamping forces are required.

In down milling the cutter tooth starts cutting into the rough metal with a thick chip resulting and ends byproducing a thin chip. The finish is smoother but the forces tend to drag the workpiece along under the cutter. Any looseness in the feed system could result in vibration and chatter with more risk to the cutter. This method is used to produce a good surface finish and for small workpieces that cannot be firmly clamped.

Cutting speed HSS cutting tools , Roughing
The table below provides some very approximate cutting speed for different materials using HSS cutterson roughing cuts. For finishing cuts the speeds would increase 20% to 50%. Forcermet (cemented carbide)tipped teeth significantly higher cutting speeds are possible see table below.

Surface Speeds
Material Rough
Cut
m/min
Low Carbon Steel 24-30
Med. Carbon Steel
Annealed
23-30
High Carbon Steel
Annealed
18-25
Tool Steel
Annealed
18-25
Stainless Steel
Annealed
18-25
Grey Cast Iron 18-25
Malleable Iron 25-30
Brass 60-90
Bronze 30-60
Aluminium/ Alloys 120-300
Feeds
Feed per tooth (mm) for HSS and Different Milling Cutter Forms
Material vCutter Type
Plain
Heavy
Plain
light
Face SideEndFormSlitting
Steel Low Carbon.
0,250,150,30,150,150,10,08
Steel-Low Carbon0,20,130,250,130,130,080,08
Steel-Med Carbon0,20,130,230,130,10,080,05
Steel-High Carbon
Annealed
0,10,080,150,080,050,050,05
Stainless steel
Free cutting
0,20,130,250,130,10,080,05
Stainless steel0,10,080,150,10,050,050,05
Cast Iron-grey0,30,20,360,20,20,10,1
Cast Iron-medium0,250,150,30,150,150,10,08
Cast Iron - Malleable0,250,150,30,150,150,10,08
Brass /Bronze0,250,20,330,20,150,10,08
Aluminium/alloys0,410,20,510,30,250,180,1
Cermet Surface Speed /Feed Rates

The table below provides some indicative values for the surface speeds and feeds (mm/tooth)that can be achieved using cermet type e.g cemented carbide tipped milling cutters.

<>
Material Surface Speed
(mm/m)
Feed /tooth (mm)
Aluminum
low silicon ( < 8% )
450-550 0,12-0,18
Aluminum, Aluminum-bronze
high silicon ( > 8% )
250-350 0,13-0,2
Bronze 300-330 0,13-0,2
Cast Iron,Malleable 120-220 0,08-0,15
Cast Iron Gray 180-360 0,1-0,4
Cast Iron Nodular (ductile) 180-260 0,1-0,2
Copper 370 0,18
Inconel 30 0,08
Stainless steel-Ferr/Mart 500-800 0,05-0,15
Stainless steel- cast 150-250 0,08-0,15
Stainless steel-304 120 0,08
Stainless steel-316L 90 0,08-0,1
Steel, unalloyed 250-430 0,003-0,006
Steel, low alloy
180-360 0,08-0,15
Steel, low alloy
hardened
120-220 0,05-0,15
Steel, high alloy
annealed
120-220 0,076-0,15
Steel, high alloy
hardened
76 0,05
Steel, cast
low alloy
180-360 0,1-0,2
Steel, cast
high alloy
120-220 0,08-0,15
Titanium 30-64 0,05-0,08
Tungsten1200,05-0,1

الرجوع الى أعلى الصفحة اذهب الى الأسفل
محمد محمد أحمد
مهندس فعال جدا جدا
مهندس فعال جدا جدا
avatar

عدد المساهمات : 655
التقييم : 697
تاريخ التسجيل : 14/11/2012
العمر : 25
الدولة : EGYPT
العمل : Student
الجامعة : Menoufia

مُساهمةموضوع: رد: Milling Machines    الثلاثاء 30 يوليو 2013, 1:03 am

جزاك الله خيرا

الرجوع الى أعلى الصفحة اذهب الى الأسفل
Admin
مدير المنتدى
مدير المنتدى
avatar

عدد المساهمات : 14413
التقييم : 23257
تاريخ التسجيل : 01/07/2009
العمر : 29
الدولة : مصر
العمل : مدير منتدى هندسة الإنتاج والتصميم الميكانيكى
الجامعة : المنوفية

مُساهمةموضوع: رد: Milling Machines    الثلاثاء 30 يوليو 2013, 3:59 am

اقتباس :
جزاك الله خيرا

جزانا الله وإياك خيراً

الرجوع الى أعلى الصفحة اذهب الى الأسفل
 

Milling Machines

استعرض الموضوع السابق استعرض الموضوع التالي الرجوع الى أعلى الصفحة 
صفحة 1 من اصل 1

خدمات الموضوع
 KonuEtiketleri كلمات دليليه
Milling Machines , Milling Machines , Milling Machines ,Milling Machines ,Milling Machines , Milling Machines
 KonuLinki رابط الموضوع
 Konu BBCode BBCode
 KonuHTML Kodu HTMLcode
إذا وجدت وصلات لاتعملفي الموضوع او أن الموضوع [ Milling Machines ] مخالف ,, من فضلك راسل الإدارة من هنا
صلاحيات هذا المنتدى:لاتستطيع الرد على المواضيع في هذا المنتدى
منتدى هندسة الإنتاج والتصميم الميكانيكى :: المنتديات الهندسية :: منتدى المقالات والمواضيع الهندسية-