Deep-drawing operation

Neutral cleaners (non-caustic based) These are ethylene oxide condensates, and easily emulsify the mineral oils and greases. They are more useful for sheet-metal components, which contain no lead compound lubricants (as used for deep-drawing operations), and are also suitable for non-ferrous... 

Slides Necked tensile specimens of metals deep drawing operations and deep-drawn cans, etc. 

Figure 10 Defects occurring in deep-drawing operations (a) wrinkling in the flange, (b) wrinkling in the wall, and (c) earing. (From Ref. 20.)...

Phosphate Coating as an Aid in Forming Steel. The contact pressure used in deep-drawing operations sets up a great amount of friction between the steel surface and the die. The phosphate coating of steel as a metalforming lubricant, before it is drawn ... 

All forming, bending, stamping, and deep drawing operations are normally performed cold. Heavy sections can be heated for forging to approximately 425°C. 

No. 2B finish. Material with a 2D finish is given a subsequent Ught skin pass cold-rolhng operation between pohshed rolls. A No. 2B finish is the most common finish produced and is called for on sheet material. It is brighter than 2D and is semirefiective. It is commonly used for most deep drawing operations and is more easily polished to the final finishes required than is a 2D finish. 

One of the most demanding applications for any internal lacquer is in deep drawn food cans. Here the sheet is coated and then deformed to give a food can. The internal lacquer must withstand the tremendous deformation and still possess all of the otho properties required. At this point in time, no water based lacquer will successfully withstand this deep drawing operation and still perform. 

Fig. 13. Various forming operations (a) backward extmsion (b) deep drawing (c) spinning (d) bending (e) stretching (f) stamping (g) coining (h)...

At first sight, the same is true of aluminhim alloys. But because they are heavily alloyed (to give a high yield strength) their ductility is low. If expense is unimportant, this does not matter, some early Rolls-Royce cars (Fig. 27.6) had aluminium bodies which were formed into intricate shapes by laborious hand-beating methods, with frequent annealing of the aluminium to restore its ductility. But in mass production we should like to deep draw body panels in one operation - and then low ductility is much... 

Also, most nf the mechanical properties and corrosion resistance are improved. The alloys find wide application for operations that require ductility in the cold condition, as in stamping, spinning, deep drawing, and for articles lo be plated. An alloy widely used as a spring material because of ils high tensile and fatigue properties has the composition Cu. 55% Zn. 27% Ni, 18%. 

The normal forming temperature is the heat at which the sheet should be formed under normal operation. This temeprature should be reached throughout the sheet. Shallow draws with fast vacuum and/ or pressure forming will allow somewhat lower sheet heat and thus a faster cycle. Higher heats are required for deep draws, prestretching, detailed mold decorations, etc. 

Sometimes called drawing, cup drawing, or radial drawing of metal sheet, deep drawing is used to produce deep, round cups or containers by a process in which a flat sheet blank is firmly held by hold-down forces while the central portion of the sheet is impacted by a flat-bottomed punch into a desired shape, without the formation of wrinkles of the side wall (Fig. 7) [17]. This operation draws (pulls) the edges of the blank inward to form the wall of the cup (or container). The metal is stretched radially by the tensile forces produced by the punch, but it is compres.sed circumferentially (or in the perpendicular direction) as its diameter... 

The blankholder force (BHF) is one of the most important parameters in deep drawing. Its main purpose is to prevent wrinkling during the drawing operation... 

It is a common practice in deep-drawing and stretch-forming operations to design the drawbead to change the restraining force locally under a relatively low blankholder force and to control the flow of the sheet blank into the die cavity... 

---