Pressing green bodies - Revision history

W.rheinheimer: /* Square bars */

2021-08-23T12:46:08Z

‎Square bars

W.rheinheimer: /* Round Pellets */

2021-08-23T12:42:14Z

‎Round Pellets

W.rheinheimer: /* Square bars */

2021-08-23T12:41:51Z

‎Square bars

W.rheinheimer at 12:41, 23 August 2021

2021-08-23T12:41:24Z

W.rheinheimer at 12:41, 23 August 2021

2021-08-23T12:41:05Z

W.rheinheimer: /* Round Pellets */

2021-08-23T12:37:55Z

‎Round Pellets

W.rheinheimer at 12:37, 23 August 2021

2021-08-23T12:37:33Z

W.rheinheimer at 16:42, 1 July 2021

2021-07-01T16:42:02Z

W.rheinheimer: /* Do I need Cold Isostatic pressing? */

2021-07-01T16:40:48Z

‎Do I need Cold Isostatic pressing?

W.rheinheimer: /* Measuring the green density */

2021-07-01T16:38:54Z

‎Measuring the green density

@@ Line 28: / Line 28: @@
 '''Quantity of powder'''
-To obtain a square face of the green body after pressing, the height of the mold must be adjusted using spacers. This requires knowledge of the Shrinkage during pressing.
+To obtain a square face of the green body after pressing, the height of the die must be adjusted using spacers. This requires knowledge of the Shrinkage during pressing.
 '''Filling the Die'''
@@ Line 36: / Line 36: @@
 [[File:Nudelsuppe.jpg|thumb|center]]
-Place two spacers on top of the long punch and then put the two conical walls, with the smaller side up, on top to form the mold. Hold the walls in place with the union ring, the inside of which is also conical. Fill the powder a little bit over the top of the pressing mold and secure that the mold is filled even. The excess powder is carefully removed with a spatula. Close the mold with the short punch and put it in the press. When the press is closed hand tight, remove the spacers.
+Place two spacers on top of the long punch and then put the two conical walls, with the smaller side up, on top to form the die. Hold the walls in place with the union ring, the inside of which is also conical. Fill the powder a little bit over the top of the pressing die and secure that the die is filled even. The excess powder is carefully removed with a spatula. Close the die with the short punch and put it in the press. When the press is closed hand tight, remove the spacers.
-Platzhalter Fotos
+{| class="wikitable"
 == Pressing ==

@@ Line 9: / Line 9: @@
 == Round Pellets ==
 '''Quantity of powder'''
 To obtain a given size of the green body after pressing, the amount of powder needs to be approximated. This requires knowledge of the green density and the density of the material itself.
@@ Line 14: / Line 15: @@
 '''Filling the die'''
 First, the die should be cleaned carefully to prevent contaminations and to assure that no powder particles are squeezed between the die and punches.
 [[File:Bild4.jpg|thumb|center|Typical pressing die.]]

@@ Line 25: / Line 25: @@
 == Square bars ==
 '''Quantity of powder'''
 To obtain a square face of the green body after pressing, the height of the mold must be adjusted using spacers. This requires knowledge of the Shrinkage during pressing.
 '''Filling the Die'''
 First, the die should be cleaned carefully to prevent contaminations and to assure that no powder particles are squeezed between the die and punches.
@@ Line 34: / Line 37: @@
 Platzhalter Fotos
 == Pressing ==

@@ Line 29: / Line 29: @@
 First, the die should be cleaned carefully to prevent contaminations and to assure that no powder particles are squeezed between the die and punches.
-[[File:Nudelsuppe.jpg|thumb]]
+[[File:Nudelsuppe.jpg|thumb|center]]
 Place two spacers on top of the long punch and then put the two conical walls, with the smaller side up, on top to form the mold. Hold the walls in place with the union ring, the inside of which is also conical. Fill the powder a little bit over the top of the pressing mold and secure that the mold is filled even. The excess powder is carefully removed with a spatula. Close the mold with the short punch and put it in the press. When the press is closed hand tight, remove the spacers.

@@ Line 8: / Line 8: @@
 == Round Pellets ==
 To obtain a given size of the green body after pressing, the amount of powder needs to be approximated. This requires knowledge of the green density and the density of the material itself.
 Calculate the Volume of the required green body. Multiply with the green density and the density of the ceramic material itself. the result is the amount of powder required for pressing the green body.
-To fill the die, first, it should be cleaned carefully to prevent contaminations and to assure that no powder particles are squeezed between the die and punches.
+'''Filling the die'''
 [[File:Bild4.jpg|thumb|center|Typical pressing die.]]
 The lower punch is put into the die. The desired amount of powder is weighted on paper and filled into the die. Make sure to evenly distribute the powder within the die, e.g. by shaking. Insert upper punch. Put the die into the press. Remember to hold the lower punch.
@@ Line 20: / Line 22: @@
 | [[File:Bild3.jpg|thumb|center|Weighting the powder]] || [[File:Bild1.jpg|thumb|center|Powder evenly distributed within the die]] || [[File:Bild2.jpg|thumb|center|Die with upper punch.]] || [[File:Bild5.jpg|thumb]]
 |}
 == Pressing ==

← Older revision		Revision as of 16:42, 1 July 2021
Line 1:		Line 1:
−	Pressing green bodies is an essential step of ceramic processing. As powder is being handled, make sure to wear PPE and use a hood whereever possible.	+	Pressing green bodies is an essential step of ceramic processing. There are many ways of pressing green bodies. This article focusses on axial pressing.
		+
		+	As powder is being handled, make sure to wear PPE and use a hood whereever possible.

	== Powder properties for good pressing ==		== Powder properties for good pressing ==

← Older revision		Revision as of 16:40, 1 July 2021
Line 48:		Line 48:

	== Do I need Cold Isostatic pressing? ==		== Do I need Cold Isostatic pressing? ==
		+	Cold isostatic pressing (CIP) assures a homogeneously high green density, which is always good for sintering. If there are issues with remaining proosity, inhomogeneous shrinkage or distortion after sintering, is is worth to add a CIP treatment after axial pressing.

← Older revision		Revision as of 16:38, 1 July 2021
Line 45:		Line 45:

	== Measuring the green density ==		== Measuring the green density ==
		+	Measuring the green density is easily done geometrically by calculating the volume from the dimensions. Remember that after Cold isostatic Pressing, the shape of the green body can become irregular so that measuring the diameter and height can be difficult. In this case, measurign the green density is difficult.
		+
	== Do I need Cold Isostatic pressing? ==		== Do I need Cold Isostatic pressing? ==