Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
  • B30B11/02—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space
  • B30B11/08—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space co-operating with moulds carried by a turntable
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
  • B30B15/06—Platens or press rams
  • B30B15/065—Press rams

Definitions

• the present invention relates to the field of the manufacture of compacts from powders or granules in particular, and more particularly a compaction machine for forming such compacts by compaction or compression.
• Compaction machines for making compacts by compaction are conventionally rotary presses equipped with a rotating central plate in which a plurality of through dies is formed.
• On either side and facing each of the matrices are arranged lower and upper punches complementary to each other, and intended to be inserted into the corresponding matrix to compact the mixture it contains in order to form a compact.
• the punches are provided with compaction ends whose surfaces define, with the walls of the matrix, a volume of containment of the mixture. During compaction, the punches are progressively brought closer to one another until reaching the predefined compaction volume.
• punch holders which punch holders have a head that moves frictionally in cam paths with significant lubrication.
• the punch holder within the meaning of the present invention is sometimes referred to as a "punch holder" by those skilled in the art.
• punch holder and “punch holder” denote the piece extending from one end, designated head, to the opposite end, receiving the punch.
• Punch supports are also known whose rollers roll in a guide rail by means of a head whose particular shape allows rolling in a cam path.
• a description of this type of punch holders is available in the publication WO2010 / 007152 A1 of the applicant.
• the lubrication of these systems is generally done using so-called "conventional" lubricants.
• conventional lubricants are meant lubricating oils, lubricating greases, or any other lubricant that must be applied continuously or frequently. It is therefore understood that the aforementioned systems therefore use conventional lubricants which are distinguished in particular from a solid lubricant.
• An object of the present invention is to provide a punch holder moving system that significantly reduces friction and wear of the contact areas in the cam path.
• An object of the present invention is to provide a punch holder moving system which does not require any use of conventional lubricants on the elements allowing the displacement of said supports in guide portions without effort of the cam path and which requires only a very small amount of lubricant on the elements allowing the displacement of said supports in guide portions with effort of the cam path.
• a punch holder for making compacts, said punch holder having a longitudinal axis and being adapted to be moved in the machine by translation along its longitudinal axis, said punch holder comprising a head intended to be guided. in a cam path of the machine, characterized in that the head has for this purpose:
• a bearing surface adapted to slide against the cam path and shaped so as to come into contact with the cam path so that in the stationary position of the punch holder in the cam path, the reaction of the cam path on the head of the punch holder results in a force parallel to the longitudinal axis
• a roller arranged to roll on the cam path during the displacement of the punch holder in guide portions with cam path force so that the reaction of the cam path on the punch holder result in a force parallel to the longitudinal axis.
• the stationary punch holder is considered to eliminate any frictional forces that could generate a tangential component of the reaction force of the cam path on the punch holder.
• the punch holder has an elongated body along the axis of displacement of the punch holder, having a constant orthogonal section.
• the punch holder has an elongate body section having at least one, preferably four, straight sides parallel to the axis of axial displacement of the punch holder.
• the punch holder has a head in the form of a piece of revolution or one or more pads.
• the punch holder comprises two coaxial parallel rollers.
• the punch support may comprise two centering bearings forming a cylinder on which the roller is arranged along a transverse axis.
• the punch holder has a roller made from a stainless steel grade martensitic, preferably corresponding to the grade X39CrMo17-1, and having bearing bearings side manufactured in a polymer grade, preferably polyetheretherketone, the commercial designation being KETRON PEEK 1000.
• the punch support has a head made from a martensitic stainless steel grade, preferably X105CrMo17.
• the rolling roller of the punch holder protrudes from the sliding bearing surface.
• the invention also relates to a cam path adapted to guide the punch holder and comprises:
• a first guiding portion adapted to come into contact with the bearing surface of the head and allowing the frictional guidance of the head
• a second guide portion adapted to serve as a raceway for the roller.
• the cam path can be adapted to guide a punch holder in which the guide portions with effort represent 10% to 40% of a compaction cycle, and preferably 5% to 20% of a compaction cycle. .
• the cam path may be adapted to guide a punch holder in which the movement of the punch holder in the portions guidance without effort is made without any use of conventional lubricant.
• the cam path adapted to guide the punch support is made from a material, preferably polyethylene terephthalate (PET) marketed under the name ERTALYTE TX, and still more preferably polyethylene terephthalate added with a solid lubricant.
• PET polyethylene terephthalate
• the second guide portion of the cam path adapted to serve as a rolling track for the roller has a stainless steel insert constituting the raceway, the martensitic stainless steel shade preferably X39CrMo17-1.
• the method of using the punch and the cam makes it possible to manufacture compacts in a compacting machine.
• compacts are made from the method of using the punch holder and the cam.
• said compacts can be made from powders or granules.
• Figure 1 is a three-dimensional representation of the punch holder.
• Figure 2 is a three-dimensional representation in axial section of the punch holder.
• Figure 3 is a three-dimensional representation of the punch holder in an effortless guide portion of the cam path.
• Figure 4 is a three-dimensional representation in axial section of the punch holder in a guide portion with effort of the cam path.
• FIG. 5 schematically illustrates the kinematics of the passage of the punch support from the effortless part to the effort part of the cam path.
• a punch holder 2 carries a punch 4 at one of its ends.
• the punch holder 2 has a head 6 at its opposite end and a body elongate along a longitudinal axis, which is parallel to the direction in which the punch 4 and its support 2 move relative to a molding die (not shown). during operation of the compacting machine (not shown).
• the orthogonal section of the elongate body is constant, which allows said body elongated to slide in an axial guide (not shown) of the compaction machine during the movement of the punch.
• the elongated body has four flats 3 (but it could include a different number), which are parallel to the longitudinal axis.
• the axial guide in which the elongated body slides has a section of corresponding shape, which ensures the rotational locking of the punch holder 2.
• the head 6 is a piece of revolution which has a bearing surface 8 smooth, that is to say devoid of sharp edges, able to slide only by friction (that is to say without rolling) against a cam track 20
• the bearing surface 8 extends all around the head 6. It thus generally has a distal face 8a and a proximal face 8b each approximately in the shape of a spherical cap, the two distal and proximal faces joining together on the maximum diameter 8c of the head 6. It can be seen that the head 6 has a rectangular shaped lumen 10 located in the axis of the punch support and therefore in the central part of the distal face 8a of the bearing surface 8.
• a roller 12 is positioned in line with the light 10 and this roller 12 protrudes from the distal face 8a of the bearing surface 8.
• Different types of roller bearings can be used to realize the invention. for example a single roller, but also two coaxial parallel rollers can be used.
• the roller 12 is a simple wheel made by bar turning which has no characteristic similar to that of ball bearings.
• the cam path 20 provides a contact surface with the head 6 which is shaped such that in the stationary position of the punch holder 2 in the cam path 20, the reaction of the cam path 20 on the head 6 of the cam Punch holder 2 results in a force parallel to the longitudinal axis.
• the contact surfaces between the head 6 and the cam path 20 are such that the cam path exerts on the head 6 forces whose resultant, if the head is not moving relative to the cam path, is parallel to the longitudinal axis.
• the head 6 may also take other forms than a piece of revolution, for example it may have the shape of one or more pads which have a bearing surface 8 adapted to slide against the cam path 20, provided that the above condition must always be respected as the resultant of the forces exercised by the cam on the head is parallel to the longitudinal axis.
• compaction takes place in four main phases of movement of the punches: filling, dosing, pre-compression and compression. It is also recalled that a machine has upper punches and lower punches, positioned in pairs facing each other to close a molding die of a compact and carried by opposite punch holders, whose heads move. in upper and lower cam paths.
• the head 6 is shaped to contact the cam path 20 such that in the stationary position of the punch holder 2 in the cam path 20, the reaction of the cam path 20 on the The head 6 of the punch holder 2 has a resultant force parallel to the longitudinal axis.
• the displacement by friction of the head 6 ensures a very low friction level thanks to a pair of material particularly suitable for limiting friction in this configuration.
• the bearing surface 8 of the head 6, which is preferably manufactured in a stainless steel grade, slides substantially frictionlessly in the cam path 20 which is made of a polymer material shade limiting friction.
• This pair of stainless steel / polymer material can reduce friction almost completely.
• the best pair of materials for this type of application is a steel grade X105CrMo17 coupled to a polyethylene terephthalate (PET) polymer and marketed under the name ERTALYTE TX.
• PET polyethylene terephthalate
• the polyethylene terephthalate is added with a solid lubricant well known to those skilled in the art. However, one could possibly consider in some cases, to dispense with the use of solid lubricant.
• centering bearings 14 each comprise a cylindrical portion which join to form together a cylinder 15 whose interior volume receives a holding screw 16.
• centering bearings 14 are held coaxially relative to each other along a transverse axis T through the screw 16 on which they are arranged.
• the holding screw 16 makes it possible to secure the rolling roller 12 in a position centered with respect to the head 6 by means of the centering bearings 14.
• the rolling roller 12 comprises an internal wall 17 which cooperates with the cylinder 15 formed by the centering bearings 14, according to a pivot axis connection T.
• FIG. 3 shows the punch support 2 and the cam path 20, seen in axial section and in perspective in an effortless guide portion 22.
• the cam path 20 has a profile adapted to receive the profile of the head 6.
• the bearing surface 8 is in contact with the cam path 20 and the head moves in friction.
• the roller 12 moves without contact or friction with the cam path 20, thanks to a groove 15 in said cam path having a depth greater than the height of projection of the roller relative to the distal surface of the surface support.
• FIG. 4 shows the displacement configuration of the punch support 2 in a guide portion with effort of the cam path 20.
• the force-guiding portions are guide portions of the cam path 20 where the compacting machine applies forces axial compaction or compression in order to compact the compacts to be produced.
• the cam path is configured to transmit the compaction or compression forces to the punch support by the roller 12. More specifically, the roller 12 is adapted to transmit the compaction forces at the centering bearings 14, which bearings are arranged to transmit the forces to the screw 16 which is itself arranged to transmit said forces to the head 6 of the punch holder 2.
• FIG. 5 shows an example of kinematics of a displacement of the punch support heads 6 in the cam path 20 whose profile is progressive.
• This example shows a guide portion without effort 22 and a guide portion with effort 24 which comprises for example an inclined plane of progressive compression and a fixed plane of continuous compression.
• the guide portions with effort represent 30% of a compaction cycle, but they could represent between 10% and 40% of a compaction cycle, or between 5% and 20% of a cycle. of compaction.
• the centering bearings 14 are made of a polymeric material, while the roller 12 is preferably made of stainless steel.
• the preferred grade for the roller 12 is X39CrMo17-1 and the preferred polymer grade for the bearings being a KETRON PEEK 1000 commercial polyetheretherketone.
• Table 1 below describes the physical characteristics of the polymeric materials employed. With respect to the physical characteristics of the metallic materials used in the present invention, the chemical composition is given in Table 2 below.
• the metal insert 18 has a lubrication point 18a which is at the beginning of the guide portion with effort 24 of the cam path 20.
• This lubrication point 18a of the insert 18 must be very slightly lubricated in order to eliminate friction punching supports 2 when entering the guide portion with effort 24. Long-term tests have revealed that a quantity of one cubic centimeter of grease as a lubricant, applied every fourteen hours at the point of lubrication 18a, is sufficient to reduce friction effectively.
• the metal insert 18 and the roller 12 are made from a grade of steel X39CrMo17-1.
• other materials having very good performance in the limitation of friction could be used for the manufacture of these two elements.
• the following pairs of materials could be chosen to further reduce friction to completely eliminate all lubrication; Raw Teflon / stainless steel, raw teflon / glass, raw Teflon / ceramic, glass / stainless steel, ceramic / stainless steel, ceramic / ceramic or technical polymer (Techtron) / stainless steel.
• punch holder 2 Various arrangements and variants of the punch holder 2 described above can also be envisaged depending on compact manufacturing constraints. individuals.
• shape and arrangement of the punch head 6, the cam path geometry, or the choice of materials can be varied.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Punching Or Piercing (AREA)
• Gears, Cams (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (4)

Family Cites Families (11)

• 2012
  • 2012-05-11 FR FR1254344A patent/FR2990377B1/fr not_active Expired - Fee Related
• 2013
  • 2013-05-13 CN CN201380037231.3A patent/CN104428129B/zh not_active Expired - Fee Related
  • 2013-05-13 EP EP13727634.1A patent/EP2846991A1/de not_active Withdrawn
  • 2013-05-13 WO PCT/FR2013/051046 patent/WO2013167849A1/fr active Application Filing

Non-Patent Citations (2)

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