Method and device for checking injection-molded parts, in particular pipette tips

Description

[0001] The invention relates to a method and a device for checking elongated injection-molded parts, in particular pipette tips, in a holding device such as a workpiece carrier.

[0002] Such a method is known from DE 10 2014 102 280, wherein the deviation of the pointed end of the pipette tip from the axial direction is determined using a camera in the axial direction above a pipette tip and a camera below the pipette tip. With this method, for example, a correctly shaped pipette tip that is tilted in the workpiece carrier is not detected and is rejected simply because the deviation of the pointed end of the pipette tip from the specified axial direction is assessed as a defect due to the misalignment of the pipette tip in the workpiece carrier. Since pipettes themselves and workpiece carriers often have unevenness such as burrs on the bore edges, unnecessary rejects often occur due to the tilt of the pipette tip in the workpiece carrier.

[0003] EP 1 677 070 A1 discloses a method for determining the deflection of a connecting element, wherein a first image and a second image are acquired, and respective reference points within the images are determined. By connecting the reference points, a reference axis is determined relative to the ideal longitudinal axis of the connecting elements. At a first and second test point between the reference points from a different perspective, the deviations from the reference axis to the longitudinal axis are determined, and the actual deflection of the connecting elements is calculated using the Pythagorean theorem.

[0004] Further prior art according to DE 10 2014 102 280 B3 discloses a method for assessing pipette distortion during pipette tip production. In this method, a camera positioned axially above a pipette tip and a second camera positioned below the pipette tip are used to determine any deviation of the tip end from the axial direction. Deformation of pipette tips can be detected using this method.

[0005] The object of the invention is to improve the known method in such a way that the reject rate of injection-molded parts is reduced and good parts are not rejected as rejects simply because they are positioned in an inclined position in the holding device.

[0006] This object is achieved by a method having the steps according to claim 1 and by a device having the features according to claim 9. Advantageous embodiments and further developments of the invention are the subject of the dependent claims.

[0007] This object is essentially achieved according to the invention in that a reference area extending in the axial direction on the elongated injection-molded part is detected in the workpiece carrier and the injection-molded part is measured starting from the reference area, as stated in claim 1.

[0008] In particular, the invention relates to a method for checking elongated injection-molded parts P with an axis of symmetry S, in particular pipette tips, in a holding device H, according to claim 1.

[0009] The reference area RP extending in the axial direction of the injection-molded part is scanned by an electronic detection device aligned laterally or transversely to the symmetry axis of the injection-molded part.

[0010] The reference region RP can be configured in various ways. A flat reference region is preferred, for example, in the form of the outer surface of a rotationally symmetrical injection-molded part such as a pipette tip. Corner points on a rectangle, for example, can also be provided as a reference region, from whose data the axis of symmetry can be calculated. In this case, for example, the four corner points of a rectangle are to be detected by the electronic detection device looking laterally at the axis of symmetry.

[0011] Even when four corner points are arranged, the reference area extends in the axial direction or in the direction of the axis of symmetry resulting from the reference points.

[0012] The reference region is preferably selected in a stable or thicker-walled area of ​​the injection-molded part because this area is more stable with respect to deformation than a thin-walled area. In other words, the reference region RP is provided in measuring area 1.

[0013] Advantageously, a tolerance range T is defined around a symmetry axis S calculated from the reference range RP and it is calculated whether the position of the symmetry axis section S2 determined by measurement lies within the tolerance range T or not.

[0014] As already mentioned, a lateral surface or a part of a lateral surface on a rotationally symmetric injection-molded part P is advantageously used as the reference area RP in the first measuring area 1.

[0015] Lines or individual points of a surface can also be selected as a reference area.

[0016] It is also possible to use at least one surface of the injection-molded part lying transversely to the axis of symmetry (S) as the reference region RP. For example, two axially spaced cross-sectional surfaces of the injection-molded part lying transversely to the axis of symmetry S can be used as the reference region. For an injection-molded part in the form of a pipette tip made of transparent material, the cross-sectional surfaces can be scanned by the electronic detection means arranged laterally of the axis of symmetry to measure the wall thickness of the pipette tip. From this, the axis of symmetry can be calculated from the thickness dimensions of the cross-sectional surfaces.

[0017] In order to detect an inclined position of the axis of symmetry relative to an axis of the holding device, the reference area, which can essentially be detected laterally on the injection-molded part, is detected by a detection means such as an electronic camera, which is directed transversely to the axis of symmetry onto the reference area.

[0018] To detect a curvature or slant of the injection-molded part, the position of a symmetry axis section S2 of the injection-molded part is measured by a detection means such as an electronic camera, which is directed in the axial direction onto the second measuring area 2 of the injection-molded part or by a detection means which detects its position laterally or transversely to the symmetry axis section S2.

[0019] In order to save on electronic recording equipment, it is advantageous if the position of the symmetry axis section is recorded both in the axial direction and the measurement data of the reference area are recorded transversely to the axial direction using a recording device or a camera with mirror deflections.

[0020] The method according to the invention is advantageously carried out with a device for checking elongated injection-molded parts P with an axis of symmetry S, in particular pipette tips, in a holding device H, comprising a computing unit C in which a reference area R on the injection-molded part to be measured is specified as the calculation basis, wherein a reference axis RA can be calculated from the data of the reference area R, at least one detection means K1 which is directed transversely to the axis of symmetry S of an injection-molded part P held in the holding device H and is designed such that the detection means detects a reference area RP on the injection-molded part P corresponding to the reference area R specified in the computing unit C and calculates an axis of symmetry S of the measured reference area RP from the measurement data,and at least one further detection means K2 for measuring the axis of symmetry S in a second measuring area 2 at a distance in the axial direction from the first measuring area 1.,

[0021] Advantageously, the detection means in the first measuring area 1 and / or in the second measuring area 2 are offset by 90° to each other and directed towards the axis of symmetry of the injection-molded part.

[0022] In this case, the detection means in the first measuring area 1 can be aligned transversely to the axis of symmetry of the injection-molded part and in the second measuring area 2 can be directed in the axial direction towards an end face of the injection-molded part.

[0023] In the first measuring range, detection means spaced apart in the axial direction can be directed laterally towards the axis of symmetry, for example to detect a cross-sectional area of ​​the injection-molded part.

[0024] Electronic recording devices can be electronic cameras, interferometers or infrared sensors, 3D sensors or stereo cameras, whereby different recording devices can also be provided in different areas.

[0025] It may be advantageous to provide a mandrel for receiving a rotationally symmetrical injection-molded part, such as a pipette tip, which has a contact surface that fits snugly against the inner circumference of the pipette tip and has the reference area on an exposed outer section that is scanned laterally by a camera.

[0026] Such a metrological extension of the injection-molded part can, for example, also be provided on a flat injection-molded part that is connected to the injection-molded part in a fitting manner.

[0027] Advantageously, the mandrel is provided with a bore in the longitudinal direction for applying negative or positive pressure so that a pipette tip can be sucked in and then stripped off again by positive pressure.

[0028] The mandrel can advantageously be mounted so that it can rotate in order to measure the mandrel position or its axis of symmetry by rotating the mandrel.

[0029] To strip the injection-molded part or pipette tip from the mandrel, a sleeve can be provided at the outer free end of the mandrel, which is movable relative to the mandrel in the axial direction of the mandrel or vice versa. Instead of a sleeve, another mechanical element can also be provided for stripping a pipette tip from the mandrel.

[0030] Examples of embodiments of the invention are explained in more detail below with reference to the drawings. Fig. 1 a sketch to explain the measuring method, Fig. 2 a pipette tip in a side view with different axes, Fig. 2 a schematic of the tip of a pipette tip as a detail from Fig. 2 , Fig. 3 schematically shows a measuring arrangement with a different detection of the reference area RP, Fig. 4 schematically shows a further modification of the measuring arrangement in the reference area, and Fig. 5 schematically shows detection means in the interior of the pipette tip.

[0031] Fig. 1 shows schematically an injection-molded part P, which can also be a flat injection-molded part, with an axis of symmetry S corresponding to the longitudinal axis of the elongated injection-molded part P.

[0032] K1 denotes an electronic detection device, e.g. a camera, which is directed laterally towards a rectangular reference area RP.

[0033] With K2, a second electronic detection device, e.g. a camera, is directed in the axial direction from below onto the injection-molded part P.

[0034] In the electronic detection device K1 or a computing unit C connected to it, a rectangular reference area R is specified as the reference area to be detected. A reference axis RA can be calculated from the center between the two long sides of the rectangular reference area R, for example, in the computing unit C connected to the camera K1.

[0035] Fig. 1a shows the specified reference range R with the resulting reference axis RA. These specifications in Fig. 1a are specified as zero value or base and stored, for example, in the calculation unit C in order to carry out the necessary calculations of the axis positions specified below.

[0036] H denotes a holding device such as a workpiece carrier, in whose bore the injection-molded part P is positioned in an inclined position.

[0037] The reference area RP to be measured on the injection-molded part P is selected such that the symmetry axis S of the injection-molded part P can be calculated from the measurement data of the reference area RP.

[0038] If correctly imaged by the camera K1, the reference area RP on the injection-molded part P forms the reference area R specified in the computing unit C. The reference area RP on the injection-molded part P is therefore selected in advance and its correct reproduction is taken, for example, from a drawing of the injection-molded part P and stored in the computing unit C as a zero base.

[0039] When checking the position of a pipette tip P in the workpiece carrier H, the reference area RP is first determined in an upper end area (first area 1 in Fig. 2 ) of the pipette tip P is detected by the first detection means K1 (first step).

[0040] The symmetry axis S of the injection-molded part P is then calculated from the measurement data of the recorded reference area RP in the camera K1 or in the connected computing unit C (second step).

[0041] With the second detection means, e.g. in the form of the camera K2, the spatial position of the lower symmetry axis section S2 of the tip of the injection-molded part P in the second region 2, which is spaced apart from the first, upper region 1 in the axial direction, around the tip of the pipette tip P is detected (third step). Fig. 2a shows the second area 2 in an enlarged view.

[0042] It is then determined whether the measured spatial position of the symmetry axis section S2 in the tip area corresponds to the previously calculated symmetry axis S or not (fourth step).

[0043] If there is agreement between the spatial position of the symmetry axis section S2 and the symmetry axis S, it is assumed that the pipette tip P is correctly shaped.

[0044] However, if the view in Fig. 1 If a lateral distance or offset of the symmetry axis section S2 from the previously calculated symmetry axis S is detected, then there is a deformation of the lower end area of ​​the pipette tip P, because the axis section S2 is not located on the symmetry axis S, as is the case, for example, Fig. 2 und 2a show.

[0045] Fig. 1 shows schematically a tolerance range T around the symmetry axis S, which is specified in the computing unit C.

[0046] If the spatial position of the symmetry axis section S2 is within the tolerance range T, i.e. deviates from the calculated symmetry axis S only within this tolerance range T, the tip area is assessed as sufficiently correctly formed, so that it is not necessary to reject the measured pipette tip P as reject.

[0047] This would be necessary if the measured symmetry axis section S2 in the lower end area of ​​the pipette tip P were outside the tolerance range T around the symmetry axis S.

[0048] In the presentation of the Fig. 1 the symmetry axis section S 2 lies on the symmetry axis S.

[0049] Since in practice the symmetry axis S and the symmetry axis section S 2 of an elongated pipette tip P will usually deviate from the calculated reference axis RA, Fig. 2 und 2a the symmetry axis S and the lower section S2 are shown more clearly.

[0050] Fig. 2 shows schematically a pipette tip P with the different axes, which are shown in an enlarged view in Fig. 2a are reproduced in detail.

[0051] The symmetry axis S of the pipette tip P calculated from the measurement of the reference range RP (first range) runs in the Fig. 2 illustrated embodiment, e.g. due to an inclined position of the pipette tip P in the holder H or due to a slight deformation of the reference range RP relative to the reference range R specified in the computing unit C ( Fig. 1a ) is offset laterally to the left, so that the symmetry axis S calculated from RP already deviates from the reference axis RA calculated from R in the upper conical area of ​​the pipette tip P.

[0052] In addition, there is a deformation of the pointed end area of ​​the pipette tip P due to the fact that the overall conical lower area in the lower end area is bent again to the left in Fig. 2 is bent so that the symmetry axis section S2 of the end region of the pipette tip lies laterally from the symmetry axis S of the pipette tip, which has the above-mentioned distance from the reference axis RA, which forms the calculated zero point.

[0053] Fig. 2a shows an enlarged view of the situation in the second measuring range 2 around the tip of the pipette tip P, where V 1 represents the offset of the symmetry axis S from the reference axis RA and V 2 represents the offset of the axis section S 2 from the symmetry axis S.

[0054] If the position of the symmetry axis section S2 of the tip of the pipette tip P lies within the tolerance range T around the symmetry axis S, as Fig. 2a shows, the inspection of the pipette tip P shows that the shape is sufficiently correct.

[0055] If, however, the symmetry axis section S2 is outside the tolerance range T in Fig. 2a the pipette tip P would be rejected as being too deformed.

[0056] With this measurement it is also possible to determine exact measured values ​​of the axis position using the electronic recording device K2 in order to obtain, for example, statistical values ​​of the axis deviation.

[0057] Fig. 3 shows a schematic diagram of a measuring arrangement on a pipette tip P in a holding device H, wherein at the upper end region of the pipette tip P the thickness dimension of the upper end region of the pipette tip P is determined by viewing transversely to the axial direction by two detection means K1a and K1b arranged one below the other at a distance in the axial direction, so that two cross-sectional views of the pipette tip with rings of different thicknesses as reference regions RP 1 and RP 2 are obtained. The axis of symmetry S can be easily calculated from the two rings, which, if correctly shaped, coincides with the symmetry axis section S2 of the end region. In rare individual cases, the axis of symmetry S calculated from the measured reference region RP can coincide with the reference axis RA calculated from the specified reference region R.

[0058] The first measuring range 1 (RP 1 and RP 2 in Fig. 3 ) is preferably provided at the upper end of a pipette tip P, because this end serves to grasp the pipette tip with a laboratory device during later use of the pipette tip, whereby the laboratory device inserts the pipette tip into the narrow opening of another vessel. Due to the greater wall thickness in the upper end, the reference region RP is more dimensionally stable and less subject to warping than a region with a thinner wall thickness.

[0059] In the case of a rotationally symmetrical pipette tip, the reference area RP can, for example, be an inner and / or an outer surface in the upper end area, whereby the symmetry or rotation axis S can be calculated from the circular shape of the surface.

[0060] According to another embodiment, in a lateral view through the detection means K1, two spaced inner and / or outer surface lines can form the reference area, which result in a lateral view of the upper end area in a pipette tip on the surface, wherein the symmetry axis S located in the middle can be calculated from the spaced surface lines, as is also the case Fig. 1 shows.

[0061] According to a further embodiment, two spaced cross-sectional areas at the upper end region of the injection-molded part P can form reference regions in the form of annular cross-sectional views from which the axis of symmetry S can be calculated, as can be seen from Fig. 3 can be derived.

[0062] According to a further embodiment, the upper flat surface of a pipette tip can be used as a reference surface.

[0063] It is also possible to measure different reference ranges RP in order to compare their measured values.

[0064] In the described embodiment, the second measuring area 2, which is spaced apart from the first measuring area 1, is located at the pointed end of the pipette tip, but the second measuring area 2 can also be located at a different location on the pipette tip, in particular if it is a different elongated injection-molded part than a pipette tip.

[0065] For the two measurement processes in the first and third step, for example, two cameras K1 and K2 can be used, one of which is directed from below onto the pipette tip P in order to carry out the measurement in the third step, while another camera is directed at the first or upper end area of ​​the pipette tip P transversely to the axis of the pipette tip P in order to capture the reference area RP, as shown in Fig. 1 shows.

[0066] It is also possible to install a detection device such as a camera K2' ( Fig. 3 ) to the side, which, like the camera K1, is directed at an angle of 90° to the axis of symmetry S. Furthermore, in the first measuring area 1 and / or in the second measuring area 2, detection means, for example cameras, can be provided perpendicular to the drawing plane in addition to the reproduced camera positions.

[0067] By means of a mirror arrangement it is also possible to work with only one camera, which is directed, for example, at the reference area RP transverse to the pipette tip P and, via a mirror deflection, also captures the pointed end of the pipette tip P at the front.

[0068] Depending on the effort required, additional camera positions can also be provided to carry out the two measuring processes in the first and third steps, whereby other detection devices can also be used than cameras, such as white light sensors ( Fig. 5 ), interferometer or infrared sensors, 3D sensors or even stereo cameras, especially if an inner surface at the upper end of a pipette tip P is used as the reference area RP.

[0069] Fig. 4 shows schematically a measuring arrangement in which a mandrel 10 is inserted into the upper end of the pipette tip P in the first measuring area 1, at the exposed end of which a reference area RP is formed.

[0070] In other words, in this measuring arrangement, the reference area RP is formed separately from the pipette tip P on a metrological extension of the pipette tip P, with the mandrel 10 forming the extension.

[0071] The mandrel 10 has a lower conical section 10a, the surface F of which corresponds to the inner circumference of the conical cavity of the pipette tip P. In the illustrated embodiment, two axially spaced annular surfaces F 1 and F 2 are formed on the conical section 10a as contact surfaces, which correspond exactly to the inner circumference of the pipette tip P, so that when the mandrel 10 is inserted, a defined contact surface of the pipette tip P on the mandrel is obtained.

[0072] The annular contact surfaces F 1 and F 2 can also be combined to form a single longer contact surface F.

[0073] On the exposed outer end 10b of the mandrel, a reference area RP is formed, which is defined by a Fig. 4 not shown detection means K is used to calculate the reference axis RA of the mandrel 10 from the data of the reference area RP, which axis RA corresponds to the symmetry axis S of the pipette tip in the first measuring area 1 due to the flat contact of the mandrel 10 with the contact surfaces F 1 and F 2.

[0074] The mandrel 10 can be provided with a longitudinal bore 11 so that by applying negative pressure at the outer end of the mandrel the pipette tip P can be pushed into the Fig. 4 reproduced position can be sucked in.

[0075] In the measurement setup in Fig. 4 First, the position of the mandrel 10 is measured by electronic recording means (not shown) so that the initial data such as the reference range RP and axis 12 of the mandrel 10 are determined for further calculations.

[0076] A pipette tip P is then sucked in by applying negative pressure to the bore 11 of the mandrel 10, so that the contact surfaces F of the mandrel are in full contact with the inner circumferential surfaces of the pipette tip.

[0077] The symmetry axis S of the pipette tip P is calculated using the reference range RP, assuming that the symmetry axis S of the pipette tip P in the area of ​​contact with the mandrel is identical to the symmetry axis 12 of the mandrel 10.

[0078] The measurement in measuring area 2 at the tip of the pipette tip P can be carried out in different ways in this measuring arrangement.

[0079] The mandrel 10 can be mounted rotatably. By rotating the mandrel 10 and scanning the pointed end of the pipette tip in the measuring area 2 by an electronic detection device such as the camera K2, the deflection of the symmetry axis section S2 from the symmetry axis S during rotation can be determined. The evaluation is carried out as per the Fig. 2 und 2a described.

[0080] Furthermore, with the mandrel 10 stationary, the measurement can be carried out by means of two electronic recording devices such as cameras K1 and K2, which are arranged offset by 90° relative to each other, as can be seen from the Fig. 1 was described.

[0081] Advantageously, the image recording of the reference area RP in measuring range 1 and the tip of the pipette tip P in measuring range 2 takes place simultaneously. This results in a significant reduction of pseudo errors caused by vibrations and the like.

[0082] After the measurement, the pipette tip P can be detached from the mandrel by applying overpressure to the bore 11 of the mandrel 10 and deposited in a receiving container. Alternatively, a sleeve can be provided at the outer end of the mandrel, which can be displaced relative to it, to strip the pipette tip P from the mandrel 10.

[0083] Fig. 5 shows a further measuring arrangement for detecting the reference area RP on the inner circumference of a pipette tip P using a white light sensor 20, which scans the inner circumferential surface F of the pipette tip P, preferably by rotating the sensor 20. In the illustrated embodiment, only one sensor element 20a is provided on the white light sensor. Sensor elements spaced apart in the axial direction can also be provided, which scan two spaced circles on the inner circumferential surface upon relative rotation between the pipette tip P and the sensor 20.

[0084] Instead of a non-contact white light sensor 20, an interferometer sensor can also contactlessly scan the inner peripheral surface of the pipette tip P to detect the reference area RP, which is inserted into the pipette tip P in the same way as the white light sensor 20.

Claims

1. A method for inspecting elongated injection-molded parts (P) with an axis of symmetry (S), in particular pipette tips, in a holding device (H), comprising the following steps: - detecting a reference area (RP) extending in the axial direction of the injection-molded part (P) in a first measuring area (1) of the elongated injection-molded part (P) in the holding device (H) by detecting means (K1), wherein the reference area (RP) is selected such that the axis of symmetry (S) of the injection-molded part (P) in the reference area (RP) can be calculated from the measurement data of the reference area (RP) (first step), - calculating the axis of symmetry (S) in the reference area (RP) from the measurement data of the measured reference area (RP) (second step), - measuring the spatial position of a symmetry axis section (S2) of a second measuring area (2) of the injection-molded part (P) spaced apart in the axial direction from the first measuring area (1), including an orientation and position of an axis of symmetry within the symmetry axis section (S2) (third step), and - determining whether or not the spatial position of the axis of symmetry of the symmetry axis section (S2) of the injection-molded part (P) measured in the third step in the second measuring area (2) corresponds to the symmetry axis (S) calculated in the second step.

2. The method according to claim 1, wherein a tolerance range (T) is defined around a symmetry axis (S) calculated from the reference area, and it is calculated whether the position of the symmetry axis section (S2) determined by measurement lies within the tolerance range (T) or not.

3. The method according to claim 1 or 2, wherein a lateral surface or a portion of a lateral surface on a rotationally symmetrical injection-molded part (P) is used as the reference area (RP) in the first measuring area (1).

4. The method according to one of claims 1 or 2, wherein at least one surface of the injection-molded part (P) lying transversely to the axis of symmetry (S) is used as the reference area (RP).

5. The method according to claim 4, wherein two axially spaced cross-sectional surfaces of the injection-molded part (P) lying transversely to the axis of symmetry (S) are used as the reference regions (RP1, RP2).

6. The method according to one of the preceding claims, wherein the reference area (RP) is detected by a detection means (K1) like for example a camera, which is directed transversely to the axis of symmetry (S) onto the reference area (RP).

7. The method according to one of the preceding claims, wherein the position of the symmetry axis section (S2) of the injection-molded part is measured by a detection means (K2) like for example a camera, which is directed in the axial direction onto the second measuring area (2) of the injection-molded part (P).

8. The method according to one of claims 6 or 7, wherein by means of a camera (K) with mirror deflections, in axial direction the position of the symmetry axis section (S2) and, transverse to the axial direction, the measurement data of the reference area (RP) are recorded.

9. A device for inspecting elongated injection-molded parts (P) with an axis of symmetry (S), in particular pipette tips, in a holding device (H), comprising a computing unit (C) in which a reference region (R) extending in the axial direction on the injection-molded part to be measured is specified as the calculation basis, wherein a reference axis (RA) can be calculated from the data of the reference region (R), at least one detection means (K1) which is directed towards an injection-molded part (P) held in the holding device (H), transversely to the axis of symmetry (S) of the injection-molded part (P), and is configured such that the detection means detects a reference area (RP) on the injection-molded part (P) corresponding to the reference region (R) predetermined in the computing unit (C) and calculates an axis of symmetry (S) within the measured reference area (RP) in the reference area (RP) from the measured data, and at least one further detection means (K2) for measuring the axis of symmetry (S) in a second measuring area (2) at a distance in the axial direction from the first measuring area (1) based on an orientation and position of the injection-molded part (P) within a symmetry axis section (S2) in the second measuring area (2), wherein the computing unit (C) is configured to determine a correspondence or non-correspondence of the spatial position of the symmetry axis in the symmetry axis section (S2) in the second measuring area (2) and the calculated symmetry axis (S) in the reference area (RP).

10. The device according to claim 9, wherein detection means in the first measuring area (1) and / or in the second measuring area (2) are directed at the axis of symmetry (S) of the injection-molded part (P) at a 90° offset from one another.

11. The device according to claim 9, wherein the detection means in the first measuring area (1) are directed transversely to the axis of symmetry (S) of the injection-molded part (P), and in the second measuring area (2), the detection means are directed in the axial direction toward an end face of the injection-molded part.

12. The device according to claim 9, wherein the first measuring area (1) includes detection means (K1a, K1b) spaced apart in the axial direction laterally toward the axis of symmetry (S) of the injection-molded part (P) for detecting a cross-sectional area of the injection-molded part as a reference region (RP1, RP2).

13. The device according to one of claims 9 to 12, wherein electronic cameras, interferometers or infrared sensors, 3D sensors or stereo cameras are provided as detection means.

14. The device according to one of the preceding claims 9 to 13, wherein a mandrel (10) is provided for receiving a rotationally symmetrical injection-molded part, like for example a pipette tip (P) which abuts by means of a contact surface (F) at the inner circumference of the pipette tip (P) and has a reference area (RP) on an exposed portion (10b).

15. The device according to claim 14, wherein the mandrel (10) is provided with a longitudinal bore (11) for applying negative or positive pressure.

16. The device according to claim 14 or 15, wherein the mandrel (10) is rotatably mounted.