1、BRITISH STANDARD Founding - Equipment for the production of lost patterns for the lost foam casting process The European Standard EN 128922000 has the status of a British Standard ICS 77.180 BS EN 12892:2000 Incorporating Corrigendum No. 1 NO COPYING WITROUT BSI PERMISSION EXCEPT AS PERMITTED BY COP
2、YRIGHT LAW BS EN 12892:2000 Amd No. hit. ! National foreword comments This British Standard. having been prepared under the direction of the Eiigiiieering Sector Conunittee, was published under the authority of the Standards Committee and comes into effect on 15 Junr 2000 ! i9 ( ktober 2001 I -_ I 1
3、3533 I l -i- - ! , f- - Q BSI 19 October 200 I Spelling error corrected on front cover - -_ This British Standard is the official English language version of EN 12892:2OOO. The UK participation in its preparation was entrusted to Technical Committee ISE/NFFXJ, Foundry khnology, which has the respons
4、ibility to: - aid enquirers to understand the text; - present to the responsible European committee any enquiries on the - monitor related international and European developments and promulgate interpretation, or proposais for change, and keep the UK interests informed; them in the K. A list of orga
5、nizations represented on this committee can be obtaine on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “international Standar
6、ds Correspondence index“, or by using the “Find“ faciity of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application Compliance with a British Standard d
7、oes not of itself confer immunity from legal obligations. Summary of pages This document coniprises a front cover, an inside front cover, the EN title page, pages 2 to 16, an irside back cover and a back cover. The BSI copyrighi notice displayed in this document indical es when the document was last
8、 issu - lost foam process. - This standard concerns the lost foam process. - This standard describes the specification for tooling to produce patterns or cores for the lost foam process. This standard is intended for purchasers, manufacturers and founders. It is also intended to ensure correct inter
9、pretation of part and tool drawingdnumerical data, and to ensure pattern equipment will produce lost moulds and lost cores, suitable for use and to assist in determining the usually undefined limits of good workmanship. It stresses the need for consultation between the founder, manufacturer (pattern
10、s), manufacturer (tooling) and purchaser before wok commences. Thic standard is intended to assist interested parties in producing tooling for urea or dense polystyrene or expanded material patterns suitable for use to produce castings by the lost pattern process. There is a complex relationship bet
11、ween the parties who might be involved in specifying, manufacturing, ordering and designing the equipment within the scope of this standard. NOTE: Figure 1 gives an indication of the relationships that could exist between the four parties concerned. L - - I L Figure 1 - Model inter-relationships bet
12、ween the contracting parties This standard not only specifies the usual features of design, manufacture, materials, tolerances, contractions and required machining allowances but also specifies other features such as usage, classification, quality control, making, packaging and storage. a 6.9 19 Oct
13、ober 2001 Page 5 EN 1 2892:2000 1 Scope This standard specifies the requirements for toding for the production of lost patterns by the lost foam process. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative refe
14、rences are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the
15、 latest edition of the publication referred to applies. EN 10204 Metallic products - Types of inspection documents EN 20286-1 IS0 system of limits and fits - Part I: Bases of tolerances, deviations and fits (IS0 286-1 : 1988) IS0 8062:l 994 Castings - System of dimensional tolerances and machining a
16、llowances 3 Terms and definitions For the purposes of this standard, the following terms and definitions apply: 3.1 collapsible insert Patt made in two or more pieces to permit withdrawal from an undercut pattern surface. 3.2 contraction Provision applied to the tooling for shrinkage occurring durin
17、g the production of castings. 3.3 dowel register Component which ensures accuracy of fit or alignment between mating portions of the tooling. 3.4 taper Draft angles on surfaces of tooling parts or lost patterns which enable the tooling parts or the lost patterns to be withdrawn. 3.5 fixing One or mo
18、re components which ensure that the parts of the tooling are held together securely and accurately. 3.6 insert or loose piece Patt which is removed by hand or by mechanical means from the pattern before or during stripping and is then repositioned in the tooling. O BSI 19 October 2001 Page 6 EN 1289
19、2:2000 3.7 lost foam process Pattern casting process in which a destructible pattern material is used. NOTE: The pattern is surrounded by a heat resistant matenal prior to pouring. 3.8 manufacturer (patterns) Person or body responsible for the manufacture of lost foam patterns. 3.9 manufacturer (too
20、ling) Person or body responsible for the manufacture of !he tooling and/or ancillary equipment required to produce a lost foam pattem. 3.10 master pattern Model used to produce a pattem which includes the appropriate contractions. 3.1 1 mismatch Offcet conditions at parting line caused by misalignme
21、nt. 3.12 pattern Foam based shaped matenal. 3.13 pattern injection Process of filling the tooling cavity with expandable material. 3.14 stripping Action of removing the pattern from the tooling by hand or by mechanical means. 3.15 tooling Ail the equipment required for the production of a lost patte
22、m (except the machine used to inject the foam). 3.16 tooling cavity Intended space in the tooling into which pattem material is introduced. 3.17 tooling filling system Openings used to introduce the pattern material into the tooling. O SI 19 October2001 Page 7 EN 12892:2000 4 Order information and d
23、elivery conditions 4.1 General There shall have been an agreement made and an exchange of information carried out between the purchaser, the manufacturer (patterns), the manufacturer (tooling) and the founder by the time of acceptance of the order, to ensure a full understanding of the respective re
24、quirements of the parties concerned. 4.2 Points to be discussed As applicable, the following essential points shall be considered during the negotiation stage: - casting matenal(s) and its (their) identification; - number of patterns to be produced; - number of subelements for each pattern; - patter
25、n andlor core materials; - drawings and/or numerical data; - number of tooling cavities required; - contractions; -joint lines; - pattern joints; -tapers; - components and identification of tooling; - required machining allowances; - machining provisions and tooling finishing requirements; - toding
26、materials; -tooling quality class; - surface condition of the tooling cavity; - dimensional tolerances; - pattern stripping and cooling support systems; - tooling inspection requirements and inspection fixtures; - wnnerneeder positions and, if necessary, the system; - tooling accessories; - assembly
27、 accessories; - any other important parameters such as surface protection and packaging for transport, storage, venting and assembling arrangements. Q BSI 19 October 2001 Page 8 EN 12892:2000 4.3 Mandatory information The enquiry and order shall include information on: a) number of toolings to be su
28、pplied and the delivery requirements; b) specification(s) of the material(s) to be used in the manufacture of the tooling; c) relevant drawings andlor numerical data; d) contraction(s) to be used; e) size and position of any gating required; f) positions and sizes of blow holes for expanded material
29、; g) information on tooling mounting, connection and alignment; h) surface condition required for the tooling cavity; i) inspection(s) and documentation required; j) relevant quality class; k) any functional tests required; and, as applicable: I) additional properties not specified in the material s
30、tandards; m) special measures to be taken or specifications to be observed, particularly with regard to the testing of welds; n) repairs of tooling; o) type of protection and packaging; NOTE: Transport arrangements can be included. p) approval procedures; q) storage arrangements; r) any other requir
31、ements. 5 Classification There shall be an agreement made between the patties concerned on the quality class to be adopted. NOTE: TaMe 1 gives guidance for the selection of metal pattern equipment. O BSI 19 October 2001 Page 9 EN 12892:2000 Features Quality class M5 I M6 I Use Batchwise manufacture
32、using foam injection machines and involving high standards critical, alternatively made up from several parts 1 As for M5, but finishing not as Manufacture Material I As for M5 I Dimensional tolerances Weanniparts Loose pieces In accordance with EN 20286-1 and IS0 8062:l 994 As for M5 Long run manuf
33、acture using foam injection machines and involving high standards Worked from solid material (machined) or cast to size and suitably finished Aluminium alloys, steels and other allow sie relevant matiai See relevant material As for M5 6 Specifications 6.1 Drawings and/or numerical data and/or master
34、 patterns The purchaser shall make available to the manufacturer (tooling) any necessary drawings of the casting and/or numerical data and/or master patterns. The identification of the relevant drawings and/or relevant numerical data and/or relevant master pattern(s) shall be specified in the enquir
35、y and order. The drawing(s) shall conform to European or International Standards unless otherwise agreed. Any modifications to the drawings andlor numerical data and/or master patterns necessary to aid manufacture of the tooling shall, be agreed between the purchaser, the founder, the manufacturer (
36、patterns) and the manufacturer (tooling). The manufacturer (tooling) shall be responsible for the shape, dimension and suitability of the tooling being manufactured. 6.2 Designation The designation of the quality class on the drawings and other relevant documents shall contain the following: -the nu
37、mber of this European Standard (EN 12892); -the quality class. EXAMPLE: EN 12892 - M5 6.3 Sub-contracted services If the manufacturer (tooling) intends to subcontract design or engineering s the purchaser. 6.4 Mass Nices, he hall obtain prior approval from The design shall be such as to minimize the
38、 mass of the tooling to ease handling and preserve the integrity of the final geometry. BSI 19 October 2001 Page 10 EN 12892:2000 6.5 Tooling filling systems Agreement shall be made on the size and location of any filling system used. If it is not practicable to provide sketches of the gating system
39、 to the manufacturer (tooling), the area and size of the possible filling facility shall be given and the area shall be kept free from screws and dowels. Tooling design shall make provision for space and joint line considerations to allow the filling system to be added at a later date. 6.6 Tooling t
40、emperature If necessary, provision shall be made to ensure that the tooling temperature can be pre-set within a defined temperature range. Provision shall be made to ensure that the completion of the expansion process is within defined temperature and time limits. 7 Manufacturing requirements 7.1 Ma
41、terials 7.1.1 General Materials used in the manufacture of tooling shall meet the conditions agreed by the parties concerned. 7.1.2 Fixings All fixings shall be treated to prevent their corrosion or shall be corrosion resistant. NOTE: Attention should be paid to the need to prevent bkmetallic corros
42、ion. 7.1.3 Inserts and sliding loose pieces Inserts and/or sliding loose pieces shall be made preferably from material different to that of the tooling case or frame to reduce friction. 7.2 Manufacture 7.2.1 General The following requirements, as applicable, shall be met: a) mismatch shall be within
43、 the tolerances agreed by the parties concerned; b) elements of the toding shall be designed such as to permit subsequent modifications; c) screws shall be lubricated to prevent seizing; d) working threads in aluminium alloys shall have reinforced inserts; e) wiping slots shall be provided on siidin
44、g surfaces to facilitate self-cleaning; f) all extemal corners or sharp edges on the tooling shall be chamfered or radiused. Internal sharp comers forming the pattern and external sharp comers on the tooling shall be avoided unless otherwise specified. The radius used shall be the maximum permitted.
45、 O BSI 19 October 2001 Page 11 EN 12892:2000 7.2.2 Joint lines and glue joints 7.2.2.1, Position The position of joint line(s) shall be such as to prevent flash. The position of the glue joints shall be such as to facilitate glueing. NOTE: Joint lines and glue joints should not be positioned in area
46、s where flatness is specified on the drawing. 7.2.2.2 Venting Tooling cavities shall be vented: - to ensure their adequate filling; - to aid the stripping of the pattern; - to allow for the introduction of steam for the expansion process; - to optimize the density of the foam. 7.2.3 Inserts and loos
47、e pieces 7.2.3.1 Securing methods Suitable means of securing shall be used. Removable screws shall be clearly marked to facilitate their proper repositioning. 7.2.3.2 Feather edges Feather edges shall be avoided generally in the tooling but specifically in the design of loose pieces. 7.2.4 Location
48、devices 7.2.4.1 General Location devices shall be designed so that the tooling can only be assembled in the intended sequence and position. 7.2.4.2 Dowels Dowels shall be non-reversible. If necessary, dowels shall be relieved. 7.2.4.3 Guide pins, keys and machined shoulders Guide pins, keys and mach
49、ined shoulders shall be provided as necessary to maintain alignment of tooling parts. Any pin shall be both hardened and ground. Any pin shall be tapered at its ends to facilitate closure of the tooling. If applicable, such pins shall fit hardened drill bushings to ensure accurate closure of the tooling. 7.2.4.4 Hinged tooling Hinged tooling shall be fitted with fixings that prevent movement in directions other than those which are intended. O BSI 19 October 2001 Page 12 EN 12892:2000 7.2.5 Radii and fillets Radii and fillets shall be incorporated to assist pattern removal. Such
