Method for producing hollow bodies made of plastics

Patent metadata

Field	Value
Publication number	US-11801628-B2
Application number	US-201816651714-A
Country	US
Kind code	B2
Filing date	Sep 21, 2018
Priority date	Sep 29, 2017
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

A method for producing hollow bodies made of plastics by blow molding or deep drawing using a deep-drawing tool or a blow-molding tool, comprising the extrusion of preforms from thermoplastics, the method comprising a wall thickness control of the preforms, wherein a measurement of the wall thickness of the preforms takes place within the tool on the mold cavity side on at least one reference point of a preform, the measured value obtained is compared as an actual value with a predetermined target value and the wall thickness control is triggered to change the wall thickness of the preform during extrusion or between extrusion cycles depending on the deviation between the actual value and the target value.

First claim

What is claimed is:

1. A method to produce hollow bodies made of plastics by blow molding, comprising:
extruding preforms from thermoplastics from a plurality of extrusion cycles,
providing a wall thickness control of the preforms,
placing the preforms as plasticized preforms in an open blow-molding tool,
forming the preforms into intermediate products within a mold cavity of the blow-molding tool using heat of plasticization from the extrusion,
measuring a wall thickness of at least one of the intermediate products within the blow-molding tool, from a mold cavity side of the blow-molding tool, using at least one reference point of at least one of the intermediate products, to obtain a measured value which is compared as an actual value to a predetermined target value, and which triggers the wall thickness control to change a wall thickness of at least one of the preforms between the extrusion cycles depending on a deviation between the actual value and the target value.

2. The method according to claim 1 , further comprising joining the intermediate products together to form a closed hollow body.

3. The method according to claim 2 , further comprising joining at least one built-in part to at least one of the intermediate products before the intermediate products are joined to form the hollow body, wherein the measurement of the wall thickness takes place before joining of the built-in part and wherein joining the built-in part is only carried out if the deviation between the actual value and the target value does not exceed a predetermined deviation.

4. The method according to claim 1 , wherein the intermediate products are fixed within the blow-molding tool during the measurement.

5. The method according to claim 1 , wherein the measurement is carried out by at least one measuring device comprising a tactile sensor, an ultrasonic sensor, a capacitive sensor or an optical sensor.

6. The method according to claim 1 , wherein the measurement is carried out by at least one measuring device which is installed on a tool divider, a joining frame or an intermediate frame of the blow-molding tool at at least one measuring point.

7. The method according to claim 6 , wherein the measurement is carried out as an optical measurement.

8. The method according to claim 1 , wherein the wall thickness control causes a nozzle gap adjustment on an extrusion head.

9. The method according to claim 1 , wherein a zero position setting or calibration of the measuring device is provided.

10. The method according to claim 1 , wherein the intermediate products are discharged by a given amount in an event of a discrepancy between the actual value and the target value.

11. The method according to claim 1 , wherein the measurement of the wall thickness of the intermediate products is carried out within the blow-molding tool when the blow-molding tool is open.

12. The method according to claim 1 , wherein the measurement of the wall thickness of the intermediate products is carried out within the blow-molding tool when the blow-molding tool is closed.

13. The method according to claim 3 , wherein the measurement of the wall thickness takes place in an area of a joint surface provided for the built-in part.

14. The method according to claim 5 , wherein the optical sensor is a laser sensor.

15. The method according to claim 7 , wherein the optical measurement is carried out as a laser measurement.

16. The method according to claim 9 , wherein the zero position is an initial zero position.

17. The method according to claim 9 , wherein the zero position is a repeated zero position.

18. The method according to claim 1 , wherein the plasticized preforms are sheet plasticized preforms.

19. The method according to claim 1 , wherein the intermediate products are shell intermediate products.

Assignees

• Kautex Textron Gmbh & Co Kg

Inventors

• Mayer Thomas
• Hild Jochen
• Thimm Verena

Classifications

• B29C2049/787

  Thickness · CPC title

• B29C49/04

  Extrusion blow-moulding · CPC title

• B29C49/78 Primary

  Measuring, controlling or regulating · CPC title

• B29C49/04116

  characterised by the die · CPC title

• B29L2022/00

  Hollow articles (tubular articles B29L2023/00; pneumatic tyres B29L2030/00) · CPC title