6th week words Ebubekir Çantı 030070154

1) Emulsion Cleaning (manufacturing)

Emulsion cleaning uses a mixture of a 

hydrocarbon solvent, water and emulsifying agents. 

The  solvent,  usually  petroleum-based,  comprises 

from  1 % to  10% of the total and is dispersed  in the 

emulsion as fine globules with the help of an emul- 

sifying agent (soap, glycerol, polyether or polyalco- 

hol). Workpieces are sprayed  with  the  emulsion  or 

are  immersed  in  it  with  agitation.  The  emulsion 

typically  is  heated  to  a  temperature  around  60°C 

(140°F). The process  is  useful  for removing  heavy 

deposits  of  soils from  the  workpiece,  for example, 

caked buffing compounds or mixtures of grease and 

solid material. It usually leaves a thin coating of oil 

on  the  workpiece.  A  hot-water  rinse  normally  fol- 

lows the cleaning operation. 

The method  is economical  and  safe because of 

the  high  water  content. It is commonly  used  as  an 

in-process operation. 

Handbook of Manufacturing Process-James G. Bralla, p:331

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there is no old description
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2)Acid Cleaning(manufacturing)(better)

Acid cleaning  is  very  similar to  alka- 

line  cleaning  except  that  the  alkaline  salt  is 

replaced  by  an  acid  or  acid  salt.  Otherwise  the 

method is the  same; a detergent and wetting  agent 

are also part of  the solution. Acid cleaning is supe- 

rior  to  alkaline  cleaning  in  removing  light  rust  or 

other  metal  oxides,  scale,  tarnish  and  similar 

deposits. For heavy coatings of grease and oil, acid 

cleaning  is  not  the  best  process.  The process  may 

slightly  etch  the  workpiece  surface,  but  this  is 

desirable for paint  adhesion. Aluminum, steel, iron 

and copper are often cleaned with this approach. 

Handbook of Manufacturing Process-James G. Bralla, p:331

Acid Cleaning (About Surface Treatments):(old)
Acid cleaning uses various solution containing organic acids, mineral acids, and acid salts,
combined with a wetting agent and detergent for cleaning of iron and steel. Such a cleaning
method may be used to remove oil, grease, oxide, and other contaminants without additional
application of heat.
Acid cleaning and acid pickling are quite similar processes, with acid pickling being
much more aggressive treatment, used for removal of scale from forgings or castings and
from various half-finished mill products.
Mineral acids and salts are numerous, forming either inorganic (mineral) acid solutions
or solutions of acid salts or acid-solvent mixtures. Organic components of these cleaning
solutions may be oxalic, tartaric, citric, acetic, and other acids, with acid salts such as
sodium acid sulfate, bifluoride salts, or sodium phosphates. Solvents used in this process
may be ethylene glycol or monobutyl (and other) ethers.
(Ivana Suchy, Handbook of Die Design 2nd Edition, p. 669)

3) Sewing (manufacturing)(better)

The  basic  sewing  operation  in  the 

production of garments and other textile products is 

the manually controlled sewing machine. “Its func- 

tion  is  to  form  a  chain  of  interlocking  loops  (or 

links) of  thread around small sections of  fabric.” lo 

The sewing machine  makes each  stitch and moves 

the  fabric  into  position  for  the  next  stitch  in  the 

series. Industrial machines are all powered by elec- 

tric motors and some reach speeds as high as 8000 

stitches  per  minute.  World-wide,  there  are  thou- 

sands of  different models  of  machine,  many  made 

for  special  purposes,  such  as overedging,  embroi- 

dery,  chain  stitching,  continuous  seaming,  and 

blind-stitching,  as  well  as  for  certain  operations 

such  as  pocket  sewing,  button  and  button-hole 

sewing.  However,  almost  all  have  the  common 

characteristic  of  relying  on  a  human  operator  to 

obtain  and  position  the  fabric  pieces,  direct  their 

movement  through  the  sewing  head,  control  the 

starting, the speed and stopping of the stitching, the 

movement  aside  of  the  sewn  component,  and  the 

replenishment  of  thread.  From  this  highly  manual 

system, there  has  been  an evolutionary  movement 

towards more and more automatic operation of por- 

tions  of  sewing  operations  and  also  of  complete 

operations.  Most  progress  has  been  made  with 

those  operations  that  are  more  highly  repetitive. 

The  simplest  automation  is  in  machines  that  per- 

form  an  automatic  sewing  cycle  on  fabric  pieces 

that  are manually  placed  in  position  and  manually 

set aside  after  the  operation. Examples  are  button 

or buttonhole  sewing, bar tacking, dart  sewing and 

pocket  sewing.  These  machines  are  sometimes 

referred  to  as stop motion muchines.l0 Next on  the 

degree  of  sophistication  are  semiautomatic 

machines  that  perform  such  operations  and  move 

the  sewn  assembly  aside  afterwards.  The  most 

sophisticated  machines  are  those  that  take  fabric 

pieces  from  a  hopper  or  magazine,  place  them  in 

the  sewing  machine,  perform  the  operations  auto- 

matically,  and  set  the  assembly  aside.  The  opera- 

tor’s duties are to load the hoppers  and monitor the 

machine  operation.  More  recently-developed 

machines perform these operations under computer 

control  and  can  sew  with  variations  of  size  and 

shape as dictated by  the program. 

Attachments  for  sewing  machines  improve  the 

quality and add to the productivity of certain oper- 

ations. The attachments  usually  consist  of  fixtures 

and  guides  to  direct  the  fabric  to  the  correct posi- 

tion and mechanisms to perform certain other tasks. 

They  are  frequently  used  in  production  sewing. 

Examples  include  hemming fixtures,  seam guides, 

needle positioners  (which control the height of  the 

needle  when  the  machine  stops),  stitching  tem- 

plates, thread trimmers, knives, positioners, pipers, 

gatherers, binders, rufflers and shirrers and devices 

called  stackers that remove  and  set aside the  sewn 

pieces.  They  may  do  this  by  sliding,  lifting,  or 

inverting the piece.I  Other devices move the fabric 

automatically to the correct position for sewing and 

to a new position  after the first sewing operation is 

completed. 

Some of  the  operations  performed  by  semiau- 

tomatic and more fully automatic machines are the 

following:  buttonholing,  button  sewing  with  or 

without  automatic feeding of  the buttons, tacking, 

welting, dart stitching, contour or profile sewing in 

which  curved  seams  are  sewn  automatically,  and 

pocket  setting.  Backtracking  and  angular  profiles 

can  be  sewn  automatically  on  some  machines. 

Sometimes,  two  or  more  sewing  machines  are 

arranged  in  series  so  that  the  first  machine  per- 

forms  a  sewing  operation  and  the  material  is 

moved  automatically  to  the  second  machine  for 

another  sewing  operation.  For  products  such  as 

sheets, pillowcases and table cloths, hemming may 

be  performed  on  both  edges  of  fabric  fed  to  two 

machines  from  rolls,  and  it  passes  through  the 

machines  for  continuous  sewing  and  cutting  off. 

Buttonholing and button  sewing machines may be 

made to repeat these operations at prescribed spac- 

ing on a garment. These machines are programma- 

ble so that the number of buttons and their spacing. 

can be changed when different garments or differ- 

ent sizes are sewn. 

The  sewing  machine  is  a  complex  mechanical 

device  that  performs  many  functions  with  respect 

to the thread and the fabric, each at a precise instant 

in the sewing cycle. Each machine includes devices 

to  maintain  tension  in  the thread  most  of  the  time 

and other devices to put slack in the thread when it 

is needed, machine components to move the fabric 

between  stitches  and  other  elements  to  hold  the 

fabric  motionless  when  necessary.  The  sewing 

machine needle is precisely shaped with a hole near 

the point to carry the thread and a groove to contain 

the thread when the needle passes through the fab- 

ric. The shuttle used in some stitches must oscillate 

or rotate  but  is not  solidly connected to  any  shafts 

because the thread must pass around it. Surfaces of 

all  thread  handling  elements  of  the  machine  must 

be very smooth so as not to catch the thread during 

its movement. 

There  are  two  basic  sewing  machine  stitches: 

chain stitches, which are made with one thread, fed 

from  the  top,  that  interlocks  with  itself  and  lock 

stitches, which use one thread fed from the top and 

another in a bobbin in the machine to interlace with 

the top thread. 

Chain stitches are made by a hook-like element 

called  a  looper  that  is  beneath  the  bed  of  the 

sewing machine. When a sewing needle and thread 

penetrate  the  fabric  and  start  an  upward  return 

stroke,  there  is  a  small  amount  of  slack  in  the 

thread.  The  looper  catches  the  slack  loop  and 

moves it to a position where the next needle stroke 

passes  through  it.  As  this  operation  continues,  a 

series  or chain  of  stitches  is  formed,  all  with  the 

same thread. Chain  stitches are  simpler and faster 

to  sew than  lock  stitches  and  have  more  stretcha- 

bility  but  have the possibility  of  unraveling  if  the 

thread  breaks  and one of the thread  ends is pulled 

in  a  certain  way.  Fig.  10H4(a)  shows  a  simple 

chain stitch. With  lock  stitches,  a  moving  hook  in  the 

machine bed catches the slack in the needle thread, 

just  as  a  looper  does,  but  moves  it  so  that  the 

shuttle,  which  carries  a  bobbin  of  thread,  passes 

through  the  thread  loop.  This  produces  a  bottom 

thread,  below  the  surface  of  the  fabric,  that  inter- 

locks with the needle thread from the top of the fab- 

ric. Fig.  10H4(b) shows a simple lock stitch. Lock 

stitches  essentially  remain  in  place  even  if  the 

thread should break. 

Handbook of Manufacturing Process-James G. Bralla, p:409-410,

Sewing(old)
Sewing is a common joining method for soft, flexible parts such as cloth and leather.The method involves the use of a long thread or cord interwoven with the parts so as to produce a continuous seam between them.The process is widely used in the needle trades industry for assembling garments.

(Fundamentals of modern manufacturing,materials,processes and systems,3rd edition, Mikell P.Groover, p.775)

4) Tool Wear(machinig)

The life of a cuttin g tool directly impac ts machi ning costs . The longer the
tool life is, the less the toolin g co st, an d furthermor e the few er the tool
chan ges (i. e., low er setup a nd prepa ration co sts). Despi te a century of
resear ch in th is area , mo st wear mech anism s report ed in the lit eratur e
should be treated as well-investigated conjectures, and not as proven
theorem s. Today , resear ch in this area has shifted toward monito ring and
predict ing tool wear in real time, in order to prolong tool usag e and also to
prevent catas trophi c failure of the tool. In many inst ances, breaking the
tool’s cutting edge (tip) can cause irreparable damage to the workpi ece’s
surface . Thus it woul d be prefer able to stop using the cutting too l well ahead
of this poin t.
Although cuttin g tools ha ve bee n class ified as single-poi nt and multi-point tools , many of the wear mech anisms for the former apply to the latter
as wel l. This common ality is further strengthened by the widespread use of
generi c inser ts (held in singl e- an d multipoint too l holders ) for turni ng,
milling , and even for large -diameter dr illing.
The tool regions of pa rticular inter est, from the wear poi nt of view, are
shown in Fig. 1 4. The rak e face is the prim ary surfa ce of co ntact be tween the
chip an d the cutting tool, and the flan k of the tool is a region (espec ially at
the c utting edge) where the tool comes into co ntact with the workpiece. The
geomet ries of both rake and flan k surfa ces significan tly affect cutti ng forces
and surface quality. For example , cutting-e dge strength would signi ficantly
di mini sh for back rake angles abo ve 5 j . In contrast, the cutting-edge
strength would increase as the ba ck-rake angle becom es ne gative and

ap proaches an optimal value aroun d 5 j . The end-relief angle prevent s
co ntact betw een the end flan k and the workpi ece, thou gh angles above 5 j
wi ll start weake ning the cu tting ed ge.



Manufacturing Design, Production,  Automation, and Integration, Beno  Benhabib, p:255 


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there is no old description
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5) Discontinuous Chip(metah machining)(better)


 Although continuous chips are most commonly encountered in practice, many materials form discontinuous chips under certain cutting conditions. The transition from continuous to discontinuous chip formation depends on the thermophysical properties and metallurgical state of the work material, as well as on the dynamics of the machine structure and cutting process. Transitions differ for each work material and are difficult to predict. Metals which tend to form continuous chips are usually soft, with face-centered or body-centered cubic structures and a high thermal conductivity and heat capacity (e. g. soft steels and aluminum alloys). Most metals which form discontinuous chips have a high hardness, hexagonal close-packed structure, and a low thermal conductivity (e. g. titanium alloys). Most materials, however, produce discontinuous chips under some conditions. Many materials undergo a transition as the cutting speed is increased. Low carbon steels, for example, form discontinuous chips at extremely low cutting speeds (less than 1 cm/s).

The chip initially begins to form with a relatively high shear angle. As deformation continues, the chip slides up or adheres to the rake face. This increases the frictional force and causes the shear angle to decrease and the material to bulge. As the shear angle decreases the strain along the shear plane increases until a critical value is reached, producing a ductile shear fracture. The process then starts over. Although this description is inexact it emphasizes the importance of tool-chip friction and the ductility of the work material in discontinuous chip formation. When cutting steels, discontinuous chips are more likely to occur at low cutting speeds because tool-chip temperatures are low, increasing the strength of the work material and thus frictional stresses near the cutting edge. Similarly, the use of low or negative rake angles, which increases the effective friction coefficient, also promotes discontinuous chip formation. The importance of two additional factors is not clearly indicated by this description. Discontinuous chips are also more likely to be formed when the rigidity of the tool or part is low and when the work material contains inhomogeneities. Low system stiffness increases the elastic strain energy stored in the system, especially at high feed rates, and promotes crack propagation and fracture. Similarly, inhomogeneities in the work material produce stress concentrations which promote crack nucleation and propagation.

Metal Cutting Theory and Practice Manufacturing Engineering and Materials Processing, Stephenson, David A.; Agapiou, John S., p477

Discontinuous Chip(in Metal Machining)(old description)

When relatively brittle materials (e.g. cast irons) are machined at low cutting speeds, the chips often form into separate segments ( sometimes the segments are loosely attached). This tends to impart an irregular texture to the machined surface. High tool-chip friction and large feed and depth of cut promote the formation of this chip type.

(Fundamentals of Modern Manufacturing: Materials, Processes, and Systems, Mikell P. Groover, p.491)