EP1435269A1 - Verfahren zum Verkürzen der Formgebungstaktzeit - Google Patents

Verfahren zum Verkürzen der Formgebungstaktzeit Download PDF

Info

Publication number
EP1435269A1
EP1435269A1 EP04000131A EP04000131A EP1435269A1 EP 1435269 A1 EP1435269 A1 EP 1435269A1 EP 04000131 A EP04000131 A EP 04000131A EP 04000131 A EP04000131 A EP 04000131A EP 1435269 A1 EP1435269 A1 EP 1435269A1
Authority
EP
European Patent Office
Prior art keywords
die
die surface
modified
forming
lubricant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04000131A
Other languages
English (en)
French (fr)
Inventor
Paul Edward Krajewski
John Robert Bradley
Frederick Irvin Saunders
Ravi Dr. Verma
Arianna T. Morales
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motors Liquidation Co
Original Assignee
Motors Liquidation Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Motors Liquidation Co filed Critical Motors Liquidation Co
Publication of EP1435269A1 publication Critical patent/EP1435269A1/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/053—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure characterised by the material of the blanks
    • B21D26/055—Blanks having super-plastic properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D37/00—Tools as parts of machines covered by this subclass
    • B21D37/20—Making tools by operations not covered by a single other subclass

Definitions

  • the invention relates to a method of reducing the cycle time for metal forming and more particularly to a method of reducing the part-to-part cycle time of quick plastic forming and superplastic forming of a metallic sheet alloy into an automotive sheet metal component by locally modifying a die surface to control friction.
  • an automobile sheet metal component is made by stamping or shaping a low carbon steel or an aluminum alloy sheet stock into a desired shape.
  • Automobile sheet metal components are formed and welded or otherwise joined to form vehicle body or closure panels. It is a goal to make the panels from as few parts as possible in order to minimize manufacturing cost and the overall weight of the vehicle. It is another goal to make the sheet metal components as quickly as possible to minimize manufacturing cost.
  • there is an incentive to devise more formable metal alloys and better forming processes so that fewer automobile body panels having a more complex shape can be made and joined to form either the vehicle body or closure panels rather than welding or bolting together a myriad of smaller, simpler pieces.
  • Lubrication is a critical aspect of the forming process.
  • a lubricant with a low coefficient of friction is selected to enhance material flow in a die. By minimizing friction, sticking between a blank and the die is likewise minimized, and part removal without distortion is facilitated.
  • Superplasticity is the capability of a material to develop unusually high tensile elongation with a reduced tendency toward local necking during deformation at elevated temperatures. Necking is a defect that results from excessive local thinning during forming and can ultimately lead to failure during or after forming. Alloys which exhibit superplasticity are capable of being subjected to superplastic forming, wherein portions of a preform are expanded by the application of fluid pressure against the surface of a forming member.
  • the forming member is usually in the form of a die which produces structures of predetermined shapes. The expansion of the preform occurs through an increase in the surface area of the preform produced by an elongation in the length and a reduction in thickness of individual material elements.
  • the preform In superplastic forming and quick plastic forming operations, the preform is clamped firmly at its periphery, thus ideally allowing for material to be stretched from the area inside of the clamped periphery only. Thinning of a preform as a result of stretching is highly uniform except in areas coming in contact with the forming surface. A unique area that comes in early contact with the forming surface is the forming member cavity entrance radius area, i.e., the intermediate region between the peripheral portion of the preform and the part expanding into the cavity. As the preform drapes over the radius area there is a tendency to increase the local rate of material elongation at sharp features which, in turn, may produce localized thinning or necking in this area.
  • the necking can ultimately lead to splits or tears during subsequent forming. If the forming cycle is too aggressive at a given temperature, the blank will neck and/or split just below the entry radius. Necking makes it difficult to obtain uniform thickness profiles in the structure and can lead to failure during forming.
  • a release coating which is capable of producing a high coefficient of friction has been used. The use of the release coatings in specific areas results in an increase in the frictional force and a lower net force causing material expansion, and, in turn, reduced necking at the radius area.
  • the alternative to preventing necking is to form components at very slow cycle times, which is prohibitive for high volume production.
  • the method of producing an automobile sheet metal component comprises the steps of:
  • Fig. 1 is a top view of a panel formed by a die in accordance with the method of the present invention
  • Fig. 2 a sectional view of the panel illustrated in Fig. 1 taken along line 2-2;
  • Fig. 3 is a table showing pressure-time cycle data for blanks having various friction characteristics obtained during experimentation to arrive at the method of the present invention
  • Fig. 4 is a table showing pressure-time cycle data for die surfaces having various friction characteristics obtained during experimentation to arrive at the method of the present invention
  • Fig. 5 is a graphical representation of the effect of die lubricant on a license plate pocket panel wall thickness distribution
  • Fig. 6 is a graphical representation of the effect of die lubricant on a license plate pocket panel wall thickness distribution shown in Fig. 5, compared with a graphical representation of the effect of die lubricant on a license plate pocket panel wall thickness where a die has a higher coefficient of friction at a die entry radius;
  • Fig. 7 is a partial cross-sectional view of the panel of Figs. 1 and 2 showing a die having a surface thereof modified to control the die friction;
  • Fig. 8 is a partial cross-sectional view of the panel of Figs. 1 and 2 showing a die having a metal insert to control the die friction.
  • a license plate pocket panel formed by a die in accordance with the method of the present invention.
  • the license plate pocket panel 10 was used in the development of the present invention since there exists therein a very aggressive die entry radius 12.
  • a cross-section of the license plate pocket panel 10 is illustrated in Fig. 2.
  • All testing was performed on a 1.2 mm thick aluminum alloy 5083-H18 such as that produced by Pechiney Rolled Products, Ravenswood, WV.
  • Three lubricants were also used in the testing, a Boron Nitride (BN) lubricant sold under the trademark LUBRICOAT, Milk of Magnesia or Mg(OH) 2 , and a lubricant sold under the trademark SEALMET.
  • BN Boron Nitride
  • LUBRICOAT Milk of Magnesia or Mg(OH) 2
  • SEALMET a lubricant sold under the trademark SEALMET.
  • the BN lubricant and the SEALMET lubricant were supplied by ZYP coatings, Oak Ridge, TN.
  • the SEALMET lubricant contained an unspecified mixture of metal oxides.
  • the BN lubricant was provided in two forms: (a) as an aerosol spray which contained 97% hexagonal BN and 3% magnesium silicate with an alcohol/acetone carrier; and (b) as a paint which consisted of a suspension of hexagonal BN (25 wt%) and Al 2 O 3 (4 wt%) in a water carrier.
  • the Milk of Magnesia consisted of an aqueous suspension of Mg(OH) 2 at a concentration of 80 mg of Mg(OH) 2 per ml of water. Forming was conducted on an up-acting, 320 ton hydraulic press designed for superplastic forming.
  • the first type involved forming lubricated blanks in a bare or uncoated die to show the effect on cycle time by varying lubricity.
  • the blanks were lubricated with one of two lubricants: (1) BN LUBRICOAT lubricant or (2) Milk of Magnesia.
  • the license plate pocket panel 10 was formed with the two different lubricant conditions at incrementally faster cycle times ranging from 6 minutes down to 13 seconds, to determine when necking and splitting occurred.
  • the difference in cycle time was produced by changing the pressurization rate of the forming operation, as well as by increasing the dwelling time at the peak pressure. For the sake of clarity, results are compared using cycle time, but could also be easily compared using pressurization rate.
  • each of the license plate pocket panels 10 was evaluated for necks or splits at or near the die entry radius 12.
  • the second type of experiment consisted of forming bare or unlubricated blanks in a selectively lubricated die to show the effects on necking and splitting by varying die surface friction.
  • the friction condition was varied across the die by one of two methods.
  • the first method called Pattern 1, involved spraying lubricants with extremely different lubricity on the two halves of the die. This was accomplished by masking one half of the die with tape and spraying a thick layer (approx. 0.001") of BN LUBRICOAT lubricant on the die using the BN lubricant spray. The surface was burnished by rubbing with wax paper to create a very slippery surface. The second half of the die was then sprayed with the SEALMET coating without any subsequent polishing or burnishing.
  • Blanks lubricated with either BN lubricant or Milk of Magnesia were formed in an unlubricated license pocket die at successively faster pressurization rates (i.e. faster cycle times) until necking or splitting occurred. The goal of these trials was to establish the effect of lubricity on cycle time.
  • BN lubricant and Milk of Magnesia have been previously shown to exhibit different lubricity during elevated temperature friction testing, with BN lubricant giving a significantly lower coefficient of friction.
  • the goal of the second set of experiments was to determine whether locally tailored coefficients of friction on the surface of the die could produce the same cycle time reductions that were observed for blanks lubricated with BN lubricant and Milk of Magnesia.
  • Four different lubricant test patterns were produced. Each test pattern will be described below, followed by the forming results for experiments using the described pattern.
  • the pressure-time cycles and trial results are summarized in Fig. 4.
  • the thickness profile for each "side" of a license plate pocket panel 10 formed in 4 minutes was also measured, as shown in Fig. 5.
  • the side of the license plate pocket panel 10 formed with the SEALMET lubricant coating showed more overall variation in thickness than the side of the license plate pocket panel 10 formed with BN lubricant.
  • the die entry radius 12 regions were thicker on the SEALMET lubricant side of the license plate pocket panel 10, but the bottom corners were thinner.
  • the BN lubricant side showed a more uniform thickness across the entire bottom of the license plate pocket panel 10.
  • the thickness profile indicates that while the SEALMET lubricant side of the license plate pocket panel 10 did not exhibit necking, it exhibits higher strain values at the bottom of the pocket and a less uniform strain distribution than the BN lubricant side of the panel 10. This would become an increased issue of concern if the depth of the license plate pocket panel 10 were increased.
  • Pattern 5 involved removing lubrication from the die entry radius 12 portion of the entire die. Blanks were formed at a temperature of 450 degrees Celsius using pressurization rates from 400 to 2000 psi/min. No splitting or necking at the die entry radius 12 was observed in any of the trials for Pattern 5. The fastest cycle time was 23 seconds.
  • Methods for modifying the surface 18 of the die 20 may include chemical etching, laser surface dimpling, scribing, sand blasting, laser particle injection, laser ablation, local oxidation, and combinations thereof, for example.
  • a dissimilar metal insert 22 can also be used to control friction as desired for the die 20. It is understood that other methods of controlling die friction can be used without departing from the scope and spirit of the invention.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
EP04000131A 2003-01-06 2004-01-07 Verfahren zum Verkürzen der Formgebungstaktzeit Withdrawn EP1435269A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US337239 2003-01-06
US10/337,239 US20040129052A1 (en) 2003-01-06 2003-01-06 Method of reducing cycle time for metal forming

Publications (1)

Publication Number Publication Date
EP1435269A1 true EP1435269A1 (de) 2004-07-07

Family

ID=32507436

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04000131A Withdrawn EP1435269A1 (de) 2003-01-06 2004-01-07 Verfahren zum Verkürzen der Formgebungstaktzeit

Country Status (2)

Country Link
US (1) US20040129052A1 (de)
EP (1) EP1435269A1 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8567226B2 (en) * 2008-10-06 2013-10-29 GM Global Technology Operations LLC Die for use in sheet metal forming processes
US9381548B2 (en) 2013-01-02 2016-07-05 The Boeing Company Systems for removing lubricants from superplastic-forming or hot-forming dies
US9272312B1 (en) 2013-01-02 2016-03-01 The Boeing Company Methods and systems for removing lubricants from superplastic-forming or hot-forming dies
JP6798380B2 (ja) * 2017-03-22 2020-12-09 日本製鉄株式会社 キャラクターラインを有するパネルの製造装置および製造方法
CN110193556B (zh) * 2018-02-27 2021-01-26 中国商用飞机有限责任公司 用于制造拉弯型材的模具及其制造方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55109526A (en) * 1979-02-14 1980-08-23 Fujikura Ltd Regenerating method for die
US4250950A (en) * 1978-11-03 1981-02-17 Swiss Aluminium Ltd. Mould with roughened surface for casting metals
US4269053A (en) * 1979-07-25 1981-05-26 Rockwell International Corporation Method of superplastic forming using release coatings with different coefficients of friction
JPS63108930A (ja) * 1986-10-24 1988-05-13 Toshiba Corp 金型の製造方法
JPH04167931A (ja) * 1990-11-01 1992-06-16 Mitsubishi Heavy Ind Ltd 超塑性成形における板厚制御方法
JPH04309418A (ja) * 1991-04-08 1992-11-02 Honda Motor Co Ltd 金型表面の処理方法及び金型
EP0832702A1 (de) * 1996-09-25 1998-04-01 Alusuisse Technology & Management AG Verfahren zur Herstellung von Hohlkörpern

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5035133A (en) * 1990-02-09 1991-07-30 Rohr Industries, Inc. Method and apparatus for hot die draw forming metal sheets
US5014537A (en) * 1990-06-13 1991-05-14 General Motors Corporation Convertible lockbead-drawbead
DE19833550B4 (de) * 1998-07-24 2005-10-27 Tower Automotive Hydroforming Gmbh & Co. Kg Umformwerkzeug zum Umformen mittels eines Druckmittels

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4250950A (en) * 1978-11-03 1981-02-17 Swiss Aluminium Ltd. Mould with roughened surface for casting metals
JPS55109526A (en) * 1979-02-14 1980-08-23 Fujikura Ltd Regenerating method for die
US4269053A (en) * 1979-07-25 1981-05-26 Rockwell International Corporation Method of superplastic forming using release coatings with different coefficients of friction
JPS63108930A (ja) * 1986-10-24 1988-05-13 Toshiba Corp 金型の製造方法
JPH04167931A (ja) * 1990-11-01 1992-06-16 Mitsubishi Heavy Ind Ltd 超塑性成形における板厚制御方法
JPH04309418A (ja) * 1991-04-08 1992-11-02 Honda Motor Co Ltd 金型表面の処理方法及び金型
EP0832702A1 (de) * 1996-09-25 1998-04-01 Alusuisse Technology & Management AG Verfahren zur Herstellung von Hohlkörpern

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 004, no. 158 (M - 039) 5 November 1980 (1980-11-05) *
PATENT ABSTRACTS OF JAPAN vol. 012, no. 347 (M - 743) 19 September 1988 (1988-09-19) *
PATENT ABSTRACTS OF JAPAN vol. 016, no. 467 (M - 1317) 29 September 1992 (1992-09-29) *
PATENT ABSTRACTS OF JAPAN vol. 017, no. 126 (M - 1381) 17 March 1993 (1993-03-17) *

Also Published As

Publication number Publication date
US20040129052A1 (en) 2004-07-08

Similar Documents

Publication Publication Date Title
EP2035165B1 (de) Aufweitwerkzeug zur behälterformung
US8567226B2 (en) Die for use in sheet metal forming processes
US5819572A (en) Lubrication system for hot forming
US7730753B2 (en) Lubricant for elevated temperature forming
FR2851579A1 (fr) PROCEDE D'EMBOUTISSAGE A TIEDE DE PIECES EN ALLIAGE A1-Mg
Browne et al. Optimisation of aluminium sheet forming using a flexible die
US10953806B2 (en) Roof rack for a motor vehicle
KR20010090744A (ko) 알루미늄 합금 시트메탈의 급소성 성형 방법
EP2055405B1 (de) Verfahren zum pressformen von blechen
Mori et al. Cold deep drawing of commercial magnesium alloy sheets
US6843089B2 (en) Method of producing surface features in sheet metal using superplastic forming
EP1435269A1 (de) Verfahren zum Verkürzen der Formgebungstaktzeit
KR101986330B1 (ko) 성형을 위해 최적화된 알루미늄 합금 시트
Bolay et al. Friction modelling in sheet metal forming simulations for aluminium body parts at Daimler AG
AU2011204938B2 (en) Expanding die and method of shaping containers
US20080184755A1 (en) Lubrication of magnesium workpieces for hot forming
Campbell Deformation processing
Kaimkuriya et al. Experimental and numerical investigations of Al 1100 cup using conical die without blank holder
JP3211496B2 (ja) 表面潤滑皮膜処理材およびその製造方法
CN113039026B (zh) 冲压加工用模具及冲压加工方法
RU2002135915A (ru) Способ изготовления изделий с использованием жидкой штамповки и горячей деформации
Kinsey et al. Deformation Processes
Demeri Deep drawing
Kazanowski Forming of Aluminum Alloys

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL LT LV MK

17P Request for examination filed

Effective date: 20040818

AKX Designation fees paid

Designated state(s): DE FR GB IT

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20060307