1、Designation: E874 10Standard Practice forAdhesive Bonding of Aluminum Facings to NonmetallicHoneycomb Core for Shelter Panels1This standard is issued under the fixed designation E874; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This practice describes
3、the materials, processes, andquality controls to be used in the manufacture of adhesive-bonded, aluminum-faced, nonmetallic-honeycomb-core sand-wich panels for tactical shelters.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalc
4、onversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and
5、 determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B209 Specification for Aluminum and Aluminum-AlloySheet and PlateC297/C297M Test Method for Flatwise Tensile Strength ofSandwich ConstructionsD1781 Test Method for Climbing Drum Peel for Adh
6、esivesE864 Practice for Surface Preparation of Aluminum Alloysto Be Adhesively Bonded in Honeycomb Shelter PanelsE865 Specification for Structural Film Adhesives for Hon-eycomb Sandwich PanelsE866 Specification for Corrosion-Inhibiting AdhesivePrimer for Aluminum Alloys to Be Adhesively Bonded inHon
7、eycomb Shelter PanelsE990 Specification for Core-Splice Adhesive for Honey-comb Sandwich Structural PanelsE1091 Specification for Nonmetallic Honeycomb Core forUse in Shelter PanelsE1826 Specification for Low Volatile Organic Compound(VOC) Corrosion-Inhibiting Adhesive Primer for Alumi-num Alloys to
8、 Be Adhesively Bonded2.2 Military Standards:3MIL-STD-105 Sampling Procedures and Tables for Inspec-tion by Attributes2.3 Federal Standards:3Fed. Std. No. 209 Clean Room and Work Station Require-ments, Controlled Environment3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 excess
9、ive corrosion, nsurface corrosion that is notremoved by cleaning as described in Practice E864.3.1.2 gouge, na surface defect in which material has beenremoved and that causes a decrease in strength in a highlystressed area.3.1.3 nominal pressure, nthe intended operating pressure.3.1.4 nominal tempe
10、rature, nthe intended operating tem-perature.3.1.5 tapping test, na nondestructive evaluation proce-dure for detecting panel delamination in which the outer skin ofthe panels is tapped with a hammer or coin.3.1.5.1 DiscussionChanges in acoustic emissions result-ing from tapping can be associated wit
11、h delamination andnondelaminated sections of panel.4. Significance and Use4.1 The formation of reproducible, durable-adhesive bondsin structural units requires great care in the selection ofmaterials, the preparation of the surfaces of the parts to bebonded, and the performance of the steps in the b
12、ondingprocess. Experience has shown that adhesive bonding carriedout in accordance with this practice produces relatively repro-ducible bonds.1This practice is under the jurisdiction of ASTM Committee E06 on Perfor-mance of Buildings and is the direct responsibility of Subcommittee E06.53 onMaterial
13、s and Processes for Durable Rigidwall Relocatable Structures.Current edition approved Oct. 1, 2010. Published October 2010. Originallyapproved in 1982. Last previous edition approved in 2004 as E874 04. DOI:10.1520/E0874-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcont
14、act ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dod
15、ssp.daps.dla.mil.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Facilities5.1 Panel-Assembly-Layup AreaThe panel-assembly-lay-up area is an enclosed, environmentally controlled area thatis continuously controlled for temperature,
16、 relative humidity,and concentration of airborne particles. The environmentallycontrolled area shall be maintained at a temperature of75 6 10F (24 6 6C) and not more than 50 % relative hu-midity. The temperature and relative humidity shall be re-corded continuously. All incoming and recirculated air
17、 shall befiltered to control airborne particles. The air handling equip-ment shall provide at least five air changes per hour in theenvironmentally controlled area. The filters shall ensure thatthe particle count within the environmentally controlled areawill not exceed 200 000 particles/ft3(7 3 106
18、particles/m3)ofsize 1 m and larger. The air pressure differential between theenvironmentally controlled area and adjacent areas shall bemonitored continuously and recorded at least twice weekly.The air pressure in the environmentally controlled area shall bemaintained above that of adjacent areas by
19、 a minimum of 0.015in. H2O (3.7 Pa). The particle count shall be monitored inaccordance with Fed. Std. No. 209. The recorders shall becalibrated every six months. The environmentally controlledarea shall be conspicuously identified at all entrances as limitedaccess. Unnecessary traffic within the en
20、vironmentally con-trolled area shall not be permitted. Eating and smoking withinthe environmentally controlled area shall not be permitted andthe environmentally controlled area shall be so posted. Allmaterials, tools, and equipment used in the environmentallycontrolled area shall be clean, low shed
21、, and free of lint, oil,and grease. The application of oil, grease, mold release agents,or other possible contaminants within the environmentallycontrolled area shall be prohibited. The interior, exposedsurfaces of the environmentally controlled area shall be non-shedding and easily cleaned. The flo
22、or shall be sealed andcleaned daily to minimize dust generation. No preparationssuch as insertion of foam into honeycomb core, or cleaningother than by filtered vacuum, shall take place in the environ-mentally controlled area. No core cutting shall be allowed inthe environmentally controlled area ot
23、her than that required forintegral-panel cutouts involving total thickness of the core toprecut skin openings, core repair, or minor trimming.5.2 Primer Application AreaThe primer-application areashall be separated from the cleaning tanks, manufacturing area,and other areas of potential contaminatio
24、n. All air furnished tothis area shall be filtered, and compressed air used shall beoil-free.6. Apparatus6.1 Pressure EquipmentPressure equipment for bondingof shelter panels shall be large enough to permit the bonding ofthe total panel in one step. The manufacturer shall providecalibration and test
25、 data demonstrating that the temperature onthe two facings of press platens during lamination will be equaland uniform within 4 % of their nominal temperature. Thepressure equipment used for curing the panels shall be capableof applying greater than 20 psi (138 kPa) and 300F (150C)over the entire pa
26、nel surface. Platens shall be flat to within0.002 in./ft (0.17 mm/m). The pressure equipment shall beequipped with temperature and pressure recorders and controlsthat accurately control heat-up rate, pressure application, dwelltime, cool down (when required), and pressure removal. Thepressure equipm
27、ent shall also be equipped with suitabledevices (for example, caul sheets) that facilitate moving thepanel layup into the press without misaligning the layup.6.1.1 Calibrations, Temperature and Pressure Require-ments, and ControlsGages shall be calibrated every sixmonths by an accredited independent
28、 laboratory or by themanufacturer if approved by the purchaser. The latest calibra-tion certificate shall be attached to the equipment near eachgage. It shall be demonstrated that the actual bonding pressureis within 10 % of the nominal pressure. It shall also bedemonstrated that the average tempera
29、tures of the top andbottom panel facings during the bonding process are equal anduniform to within 4 % of the nominal temperature. Thermo-couples placed at each corner and at the center of each facingshall be used to demonstrate the uniformity of the temperature.Compliance of the equipment with thes
30、e requirements shall beverified at intervals not exceeding six months. A permanentrecord of the pressure, time, and temperature measurementsduring bonding shall be maintained. All calibrations must betraceable to the National Institute of Standards and Technology(NIST).46.2 Testing EquipmentThe supp
31、lier shall have availablesufficient testing equipment to ensure that all process-controlspecimen preparation and testing required by this practice canbe accomplished without unnecessarily delaying production.All calibrations of test equipment required by this practice shallbe traceable to NIST.7. Ma
32、terials7.1 Materials shall be as specified herein or as specified inthe contract. All materials shall be stored and handled in suchmanner as to provide adequate protection against degradingenvironments and mechanical damage.7.2 Aluminum:7.2.1 FacingsThe facings shall be aluminum alloy con-forming to
33、 Specification B209 and shall be certified as com-plying with the alloy, temper, and thickness requirements of theshelter specification. Facings shall be free of excessive corro-sion, oil canning (snap-buckling), dents, gouges, or otherdefects that may adversely affect the structural integrity of ab
34、onded panel. The manufacturers certification or reports oftests for mechanical properties and chemical composition shallbe included with each shipment.7.2.2 Preparation of Aluminum-Alloy Parts for BondingThe aluminum-alloy parts used in the manufacture of honey-comb panels shall be prepared for bond
35、ing in accordance withPractice E864.7.3 Honeycomb CoreThe honeycomb-core material shallbe as specified in the shelter specification and shall meet therequirements of Specification E1091. It shall be stored in itsshipping container in a segregated area away from trafficcongestion until processing for
36、 panel layup.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.E874 1027.4 AdhesivesThe structural film and core splice adhe-sives shall conform to Specifications E865 and E990, respec-tively. They shall b
37、e stored in accordance with the manufac-turers recommendation.7.4.1 Qualification of Adhesive SystemThe panel manu-facturer is responsible for ensuring that the adhesive systemused in the manufacture of panels under this practice isqualified to meet Specifications E865 and E990.7.5 PrimerThe adhesiv
38、e primer shall conform to Specifi-cation E866.7.6 Thermal BarriersThermal barriers shall conform tothe purchasers requirements.NOTE 1Thermal barriers are bonded between the skin and metal-edgemembers to prevent a thermal short between exterior and interior skins.8. Panel Construction8.1 The alloy, t
39、emper, and thickness of the facings, edgeclosure details, core type, and the weights and sizes of thepanels shall be as specified in the design specification. Panelsshall not have any defects, bulges, depressions, or dents withan area greater than 8 in.2(5200 mm2) or deeper than 0.040 in.(1.0 mm). T
40、he total allowable area of defects per panel shallnot exceed 0.1 % of panel area per side. Panels exceeding0.1 % defect area may be subjected to rework procedure agreedupon between the manufacturer and the customer. Panels shallnot be bowed or warped nor shall there be any deviation fromtotal flatne
41、ss of the panel greater than 0.016 in./ft (1.3 mm/m).The allowable deviation from flatness (warpage) shall bedetermined by applying a straight-edge, as specified in 10.6.1,against the concave side of the panel with the opposite sidelying on a flat surface and measuring the maximum gapbetween the str
42、aightedge and the panel.8.2 Edge Closures and Framing MembersThese shall beas specified in the shelter-design specification. On pre-existingdesigns, process the material in accordance with pre-existingdesign configuration/specification requirements unless other-wise directed by the procuring activit
43、y. When the aluminumedge closures are to be bonded, they shall be treated inaccordance with Practice E864. When the shelter designrequires the edge closures and framing members to be bondedsimultaneously with panels bonding, the edge closures andframing members shall be bonded to the facings with th
44、estructural film adhesive specified in 7.4.8.3 Preparation of Aluminum Facings and Edge ClosuresAll cutting, trimming, and sizing of the facings and edgeclosures shall be made prior to surface preparation or on thepanel following completion of the bonding operation. Thefaying surfaces of all aluminu
45、m parts which are to be bondedshall be prepared in accordance with Practice E864 andSpecification E866 or Specification E1826. All aluminum forbonded panels shall be placed in primer application area within12 h after completion of the cleaning process.8.4 Preparation of Honeycomb CoreHoneycomb that
46、isnot to be filled with plastic foam shall be cleaned of dust withdry, oil-free, filtered, compressed air or vacuumed prior todelivery to the panel-assembly-lay-up area. When the cells ofthe honeycomb core are filled with plastic foam, the surface ofthe installed foam shall be at least116 in. (1.5 m
47、m) below thesurface of the honeycomb on both surfaces, and all bondingsurfaces shall be freed from foam dust and contaminants byvacuuming. When a panel requires more than one sheet of core,the seam between pieces shall be spliced so that uniformity ofthickness is maintained across the seam. The core
48、-splicingmaterial shall conform to Specification E990 and must beimpermeable to water and serve as a barrier to water migration.The core-splicing method and adhesive used shall be such thatthe shear strength of the splice shall be equal to or greater thanthe core-shear strength. Any crushed corners
49、and edges of thecore sheets shall be removed and the sheet resquared prior tosplicing and lamination. Where the shelter design requires thatall framing members be bonded simultaneously with panelbonding, the core shall fit into the panel lay-up such that thegap between the core and the framing members is no more than0.125 in. (3.2 mm) from the framing members. The volatilecontent of the honeycomb core (including moisture) at the timeof panel-assembly lay-up shall not exceed 2 % by mass whentested in accordance with 10.4.2.8.5 Application of Primer a
