Method for evaluating process characteristics of injection-molding tools

Patent metadata

Field	Value
Publication number	US-10611071-B2
Application number	US-201415028607-A
Country	US
Kind code	B2
Filing date	Oct 14, 2014
Priority date	Oct 14, 2013
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

The invention relates to a method for qualitatively and/or quantitatively classifying injection-molding tools in tool categories and determining preferred intervention ranges and/or manipulated variables for adapting injection-molding machine parameters in the case of changing ambient conditions and/or determining the influence of disturbing effects on the injection-molding process, comprising the following steps: a) providing an injection-molding machine having the injection-molding tool which is to be classified and which is intended for the determination, b) performing at least one injection-molding cycle with injection-molding machine settings in order to obtain a qualitatively adequate injection-molding part, c) determining a quotient Q=Δp/Δs or Q=Δsn/Δse characterizing the tool from c.1) a pressure rise Δp during the compression phase of the injection-molding cycle and the melt volume ΔV displaced during the compression phase or c.2) a melt volume ΔVn displaced during the holding-pressure phase and the melt volume ΔVe displaced during the injection phase, wherein c.3) the corresponding screw travel Δs, Δsn, and Δse is measured in order to determine the displaced volumes ΔV, ΔVn, and Δ; Ve, d) providing at least one limit value (G1 . . . Gx . . . Gn), wherein one or more recommendations for preferred intervention ranges or manipulated variables for adapting adjustment parameters of the injection-molding machine are associated with ranges (Q<G1; G1<Q<G2; . . . Gn-1<Q<Gn; Q>Gn) for the values of the quotient Q, e) determining in which of the ranges (Q<G1; G1<Q<G2; . . . Gn-1<Q<Gn; Q>Gn) the value of the quotient Q lies, and f) outputting the preferred intervention ranges and/or manipulated variables for adapting the machine parameters of the injection-molding machine which are associated with the determined range.

First claim

What is claimed is:

1. A method for qualitatively and/or quantitatively classifying injection-molding tools in tool categories and for determining preferred intervention ranges and/or manipulated variables for adapting injection-molding machine parameters during changing ambient conditions and/or determining an influence of undesirable effects on an injection-molding process, said method comprising the steps of:
performing at least one injection-molding cycle of an injection-molding machine, having an injection-molding tool to be classified and to be determined, with injection-molding machine settings to obtain a usable injection-molding part;
determining a quotient Q=Δp/Δs or Q=Δs n /Δs e characterizing the injection-molding tool in one of two ways, a first way in which the quotient Q is determined from a pressure rise Δp during a compression phase of the at least one injection-molding cycle and a melt volume ΔV displaced during the compression phase, a second way in which the quotient Q is determined from a melt volume ΔV n , displaced during a holding-pressure phase and a melt volume ΔV e , displaced during an injection phase, wherein a corresponding screw travel Δs, Δs n and Δs e is measured in order to determine the displaced volumes ΔV, ΔV n and ΔV e ;
providing at least one limit value G 1 . . . G x . . . G n , wherein one or more recommendations for preferred intervention ranges and/or manipulated variables for adapting adjustment parameters of the injection-molding machine are associated with ranges Q≤G 1 ; G 1 <Q≤G 2 ; . . . G n-1 <Q≤G n , Q>G n for values of the quotient Q;
determining in which of the ranges Q≤G 1 ; G 1 <Q<G 2 ; . . . G n-1 <Q<G n , Q>G n a value of the quotient Q lies; and
outputting the preferred intervention ranges and/or manipulated variables for adapting the machine parameters of the injection-molding machine which are associated with the determined range, wherein in a semi-automatic operation, the outputting takes places on a display and a machine operator transfers into a machine control values suggested by the injection-molding machine, or in a fully-automatic operation, the outputting takes place directly to the machine control whereby a next injection molding cycle is carried out with the adapted injection-molding machine parameters.

2. The method of claim 1 , wherein the pressure rise Δp is determined by measuring a course of a melt pressure or of a tool internal pressure.

3. The method of claim 1 , further comprising determining a correction factor to correct a value for the quotient Q by dynamically caused changes of the value for the quotient Q characterizing a respective tool by an influence of an injection speed.

4. The method of claim 1 , wherein recommended intervention ranges are the injection phase, the compression phase or the holding-pressure phase of the at least one injection-molding cycle.

5. The method of claim 1 , wherein the manipulated variables are a switchover point as a function of a screw position and/or a switchover point as a function of an injection pressure and/or a switchover point as a function of time and/or a holding pressure level and/or a holding pressure time and/or an injection speed and/or a cylinder temperature and/or a tool temperature.

6. The method of claim 1 , further comprising associating with the intervention ranges and/or manipulated variables as a function of the ranges Q≤G 1 ; G 1 <Q≤G 2 ; . . . G n-1 <Q≤G n , Q>G n priorities for a measure of a correcting effect of a change of the intervention ranges and/or of the manipulated variables on the injection-molding cycle, wherein the recommendations of the preferred intervention ranges and/or manipulated variables are outputted weighted with regard to the correcting effect and weighted in priority.

7. The method of claim 1 , wherein in addition to a qualitative selection of the intervention ranges and/or of the manipulated variables, correction values are outputted for the intervention ranges and/or manipulated variables.

8. The method of claim 7 , wherein the correction values are determined empirically and deposited in a data bank.

9. The method of claim 7 , wherein the correction values change values for the manipulated variables and/or definitions of the intervention ranges and/or values for priorities and/or values for correcting effects of the manipulated variables on the at least one injection-molding cycle.

10. The method of claim 7 , further comprising establishing a B characteristic diagram from the preferred intervention ranges and/or the manipulated variables and/or priorities thereof and/or the correction values thereof, and determining as a function of the quotient Q a suitable point of the characteristic diagram, wherein the correction values and/or recommendations associated with the determined point of the characteristic diagram are outputted and/or are deposited in a memory.

Assignees

• Krauss Maffei Tech Gmbh
• Kraussmaffei Tech

Inventors

• Schiffers Reinhard

Classifications

• B29C45/50

  Axially movable screw · CPC title

• B29C45/26

  Moulds · CPC title

• B29C2945/76083

  Position · CPC title

• B29C45/7646

  viscosity · CPC title

• B29C2945/76006

  Pressure · CPC title