US 3676030 A
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July 11, 1972 RQEPENACK ETAL 3,676,030
APPARATUS FOR LUBRICATION OF COMPRESSION TOOLS FOR POWDER METALLURGICAL PURPOSES Filed Oct. 22, 1969 z Sheets-Sheet 1 'I T I OI'II 1' 'I if I 'I l l I 10 f'fiI Z 'II ,C
I I 1 I I I I I l I I I I I I I I I I I I I 15 I I I l I I I l I i I f I j 1 mvsnrron 159,607 fiz'fizmacz I .J/E/Z'E 21 011044: 3y .ZZ/iz ATTORNEYS July 11, 1972 .H, RQEP EIAL 3,676,030
APPARATUS FOR RIC 0N OF COM ESSION TOOLS FOR Pow METALLURGICAL P OSES Filed Oct. 22, 1969 2 Sheets-Sheet Z 17:85)" EMF/[M406 Jar/5e A amz fe'a'z Pzaaze wd a m ATTORN United States Patent Oflice 3,676,030 Patented July 11, 1972 US. Cl. 425-48 Claims ABSTRACT OF THE DISCLOSURE There is provided an apparatus for the lubrication of compression tools for power metallurgical purposes comprising a lower die adapted to supply lubricant film, a guide for the lower part having a slightly larger diameter to insure production of a uniform lubricant film and a foot on the opposite end of the die positioned within a slightly larger distance ring which is held in position by a fixing nut, the space between the die foot and fixing nut compensating for production errors in the axis parallelism of the die bore.
In powder metallurgical technology powders which are desired to be pressed into molded bodies are preferably mixed with organic additives (lubricants) to make them machjnable. The lubricant addition is necessary because of the friction between the powder and tool. The fraction of the necessary lulbricants, which must be especially uniformly mixed, is generally so high that in addition to this working step a further processing step is necessary, namely a dewaxing ignition of the sinter. With appropriate molded bodies, the lubricant additive can be replaced by a lubrication of the compression mold wall. Such a procedure assumes to be sure that the compression tool is manufactured and installed with high precision.
This demand is only with difiiculty fulfilled, especially with the use of multiple compression tools which with each compression process manufacture a multiple number of molded bodies. Also with only slight deviation in the lubricant film thickness there results in the molded bodies because of dilferent wall frictions dilferent local densities, which after sintering lead to deviations from the desired shape, or in case of greater deviations lead to increased scrap through cracking and fissures of the sintered bodies.
To lubricate the compression mold, there is used, for example, a lower die with an axial bore through which a lubricant solution can enter from below. Near the top of the lower die the lubricant passes through radial bores to the outside and wets the mold wall with the upward and downward motion during the pressing.
Also in these cases a uniform lubricant film is not always produced because of the flaws in the tool production and in the fitting bring about substantial deviations to only a 10 to 20 p.111. thick lubricant film.
It has now been found that these flaws can be substantially reduced when the lower die of the tool has a guide part which compensates for the production flaws in the tools and in the fitting.
Preferably the longitudinal length of the guide part is greater than the diameter of the mold bore. It is especially suitable for such length to be one to three times the diameter of the mold bore.
The invention will be understood best in connection with the drawings wherein the single figure is a longitudinal sectional view of the apparatus of the invention.
Referring more specifically to the drawing there is provided a compression die which includes an end portion which is attached to a guide body 2 through an intermediate member 3.
The lubricant flows out in the space between the disc guide member 2 and the compression die end portion 1 through radial bore holes 8.
The diameter of end portion 1 is so selected that a lubricant film of preferably 10-20 #111. can be built between it and the wall 10 of mold 11. In order to guarantee an equal gap, the longitudinal length of guide portion 2 is larger than the diameter of the mold bore, preferably 1 to 3 times larger than that diameter. Guide portion 2 besides can fulfill a scaling function as can be seen from the drawings where gasket 12 is provided. In automatic lubrication processes other than that shown in the drawing the guide portion 2 can be provided with grooves. The apparatus of the invention not only allows the lubrication of compression tools for circular cylinders but also for other suitable shapes. Guide 2 compensates for eventual fitting flaws present while a suitable support or foot 4 of the die as necessary to take care of deviations in axis parallelism of the mold bore which almost always occur in multiple tools. Typical examples of such multiple tools are shown in drawing 2. Support 4 is surrounded by a structure 13 which is moveable to and away from mold 11. Support 4 is mounted so that the die can move according to the deviations of axis parallelism in the production of the lubricant film. This can be accomplished, for example, by employing a distance ring or spacer ring 5. The inner diameter of ring 5 is somewhat greater, preferably 0.5 to 1 mm., than the diameter of the die foot 4 and whose height is 0.1 to 0.2 mm. greater than that of the die foot. The distance ring is held in its position by the fixing out 6. The fixing not 6 terminates in turn the axial motion of the die in an upward direction.
What is claimed is:
I1. An apparatus for the lubrication of compression tools for powder metallurgical purposes comprising a mold having a bore therein, a structure mounted for relative movement toward and away from said mold, a die connected to said structure having a die part disposed within said bore, said die part comprising a first end portion, a guide portion for said end portion, means between said first end portion and said guide portion for supplying lubricant to the mold, said guide being of larger diameter than said first end portion to insure production of a uniform film on said mold, an opposite end portion on said die, and means permitting radial movement of said opposite end portion whereby compensation can be made for production errors in the axis parallelism of the mold bore.
2. An apparatus according to claim 1 wherein said radial movement permitting means comprises a distance ring slightly larger than and disposed around said opposite end portion and a fixing nut adjacent said distance ring and holding it in position.
3. An apparatus according to claim 2 wherein the longitudinal length of the guide portion is 1 to 3 times greater than th diameter of the mold bore.
4. An apparatus according to claim 1 wherein the guide has the same maximum diameter as the mold bore.
5. An apparatus according to claim 4 wherein the longitudinal length of the guide portion is l to 3 times greater than the diameter of the mold bore.
6. An apparatus according to claim 1 wherein said radial movement permitting means comprises a distance ring slightly larger than and disposed around said opposite end portion and a fixing nut adjacent said distance ring and holding it in position and wherein said lubricant supplying means includes an aperture in said die part for supplying lubricant and the diameter of said die part is 20 to 40 m. smaller than the diameter of the guide portion.
7. An apparatus according to claim 1 wherein said radial movement permitting means comprises a distance ring slightly larger than and disposed around said opposite end portion and a fixing nut adjacent said distance ring and holding it in position and wherein a space is provided between the fixation nut and the opposite end portion to permit an axial play of 0.1 to 0.2 mm.
8. Apparatus for the lubrication of compression tools for powder metallurgical purposes comprising: mold means defining a plurality of parallel spaced-apart mold cavities; a plurality of dies each having a first end portion slidably disposed in one of said mold cavities, and each die including internal passage means for supplying a uniform film of lubricant to the wall of its respective cavity; a structure mounted for movement toward and away from said mold means; and means connecting the opposite end portions of each die to said movable structure for movement relative thereto in a plane transverse to the axes of the dies and for movement with said structure toward and away from said mold means.
9. Apparatus as in claim 8 wherein said connecting means includes a portion of enlarged diameter on each of said dies, a plurality of distance rings each slightly larger than and disposed around one of said enlarged portions thereby permitting relative movement between each enlarged portion and its respective ring means for retaining each enlarged portion within its respective distance ring.
10. Apparatus as in claim 9 wherein each said retaining means includes a nut surrounding one of the dies and threadedly engaging said movable structure, said nut clamping the respective distance ring to the structure and being spaced from the enlarged portion of the respective die to permit a longitudinal play of 0.1 to 0.2 mm. between the die and said structure, each of said distance rings having an internal diameter which is 0.5 to 1 mm. greater than the diameter of the respective enlarged die portion.
References Cited UNITED STATES PATENTS 2,810,929 10/1957 Willi 18--16.7 2,932,063 4/ 1960 Belden et a] 18-165 3,132,379 5/1964 Crane 18-165 3,149,375 9/1964 Gehl 1816.5 3,200,442 8/1965 Haller 18-165 3,394,432 7/1968 Lament l8--16.5
J. HOWARD FLINT, JR., Primary Examiner US. Cl. X.R. 425-96, 345