hello, I am working on a tool to build virtual PCBs. Other people or organisations are probably also working on this. I have tried to use the most simple models for the dimensional and the electrical analysis. The dimensional analysis involves weight and thickness, the electrical part concerns impedances, xtalk, ... My background is in electronics and EMC engineering. It is only lately that I have began to explore PCB manufacturing. So forgive me my expressions for I am not used to the slang used in PCB manufacturing. Also I apologize for this lengthy mail. I appreciate you going through this text. I have some first results on the dimensional part. We actually have build 10 6-layer test boards and we have a simulation run using some detailed data on preg, core laminate and foil. Of these we have used very specific data of the reinforcement, of the resin and of the copper. Also included is the copper area/layer, mask data (or coating), plating details, plated perimeter of vias and the board dimensions. The preg is an Isola with 1080 reinf., the core is an Isola with 3x7628 reinf. The average finished resin content of the preg is 65+/-3%. The buildup is described below at the end of this email bewteen ** example ** and *** example done ** and although you do not know the exact input syntax, you should be able to figure out the data and the buildup intuitively (note: a comment line starts with ; or *, all other lines do something, e.g. introduce the resin, do an analysis, ...) At the bottom of the example you will the results of the weight and thickness. They are repeated here (the board is renamed to XYZ6): ***************** build summary for XYZ6 ***************** mean max min sdev preg weight: 5.09E-02 | 5.33E-02 | 4.88E-02 | 6.40E-04 core weight: 1.22E-01 | 1.26E-01 | 1.18E-01 | 1.16E-03 foil weight: 4.33E-02 | 4.76E-02 | 3.90E-02 | 1.28E-03 plate weight: 9.83E-03 | 1.25E-02 | 7.44E-03 | 7.17E-04 ----------------------------------------- total weight: 2.27E-01 | 2.33E-01 | 2.19E-01 | 2.00E-03 preg thick: 5.12E-04 | 5.41E-04 | 4.88E-04 | 7.64E-06 core thick: 1.02E-03 | 1.07E-03 | 9.68E-04 | 1.40E-05 foil thick: 6.26E-05 | 7.01E-05 | 5.57E-05 | 2.16E-06 ----------------------------------------- final thick.: 1.59E-03 | 1.66E-03 | 1.53E-03 | 1.60E-05 The colomns give the mean, the maximum, the minimum and the standard variation of the weight and thickness of the simulated buildup (in kg and m). You can also see the contibutions of the induvidual materials. The weight of the 10 test boards we build is 227.12g with a stand. dev of 1.79g. The simulation fits the measured data good with a simulated weight of 227g and a standard dev of 2g. These are my questions: (q1) Is this analysis useful? Or is this just a coincidence that the match is good? If the answer to q1 is affirmative: (q2) Does anyone use these kind of tools? (q3) Can someone supply me with the specific weight of typical FR4 resins (and also their variations) or give me directions were I can find data on these things. (q4) Is it possible to get an estimate of the thickness of a PCB by just weighing it? If a do another analysis with an overall finished resin content of 70+/-3% the weight and thickness data looks like below. The mean weight is 7g larger and the mean thickness is now 1.7mm. This simulation indicates that it is feasable! (Is this reasoning correct?) mean max min sdev preg weight: 5.93E-02 | 6.26E-02 | 5.66E-02 | 8.59E-04 core weight: 1.22E-01 | 1.26E-01 | 1.18E-01 | 1.16E-03 foil weight: 4.33E-02 | 4.76E-02 | 3.90E-02 | 1.28E-03 plate weight: 9.97E-03 | 1.27E-02 | 7.53E-03 | 7.27E-04 ----------------------------------------- total weight: 2.35E-01 | 2.42E-01 | 2.27E-01 | 2.08E-03 preg thick: 6.16E-04 | 6.56E-04 | 5.83E-04 | 1.03E-05 core thick: 1.02E-03 | 1.07E-03 | 9.68E-04 | 1.40E-05 foil thick: 6.26E-05 | 7.01E-05 | 5.57E-05 | 2.16E-06 ----------------------------------------- final thick.: 1.70E-03 | 1.77E-03 | 1.63E-03 | 1.74E-05 ***************** example ************************************* ***************** example ************************************* BUILD V1.0: build from file 'test.bui', Fri Sep 5 11:43:37 1997 ;file test.bui for initial test build code ;example XYZ 6 layer type 1 ;model type nstat model 1 3000 ******************** material data ******************** ; Isola core 510 micron, 3x7628, class 2 (+/-10%) 510 (561-459) micron ; Isola preg 1080, RC% 65 +/- 3% ; E-glass fabric 1080 46.8 g/m2, level 2 -> 45.4- 48.5 g/m2 ; E-glass fabric 7628 204.4 g/m2, level 2 -> 210.0-199.4 g/m2 ; E-glass data spw 2540 kg/m3, dk 6.1, variations unknown ; foil 18 micron 153 g/m2, level 2 -> 168.3-137.7 g/m2 ; foil 35 micron 305 g/m2, level 2 -> 335.5-274.5 g/m2 ; foil spw 9860 kg/m3, conductivity copper 17.8E-9 S/m, variations unknown ; resin data not exactly known, estimated spw 1300 kg/m3 and dk 3.6 ; mask data spw 1300 kg/m2, 1350-1250 kg/m3, estimated dk 3.0 ; thickness_over_conductor > 8 micron, thickness_over_substrate 40 micron ;plating data copper spw 9860 kg/m3, thicknes 35 micron, (25-50) micron ******************** material data ******************** ******************** build data input ******************** ;resin name spw,+,-,sdv dk,+,-,sdv resin EPON12 1300,1300,1300,0 3.6,3.6,3.6,0 ;rinf name w,+,-,sdv spw,+,-,sdv dk,+,-,sdv rinf E_1080 0.0468,0.0485,0.0454,0.0005 2540,2540,2540,0 5.8,5.8,5.8,0 rinf E_7628 0.2044,0.2100,0.1994,0.0025 2540,2540,2540,0 5.8,5.8,5.8,0 ;foil name w,+,-,sdv spw,+,-,sdv [conductivity] foil ELF_17um 0.153,0.1683,0.1377,0.0075 9860,9860,9860,0 17.8E-9 foil ELF_35um 0.305,0.3355,0.2745,0.0150 9860,9860,9860,0 17.8E-9 ;preg name rc%,+,-,sdv resin rinf preg ISOLA_1080 65,68,62,1.0 EPON12 E_1080 ;core name t,+,-,sdv resin rinf1 ... rinfn core ISOLA_3X7628 510E-6,561E-6,459E-6,10E-6 EPON12 E_7628 E_7628 E_7628 ;plate name t,+,-,sdv spw,+,-,sdv plate OUTER 35E-6,50E-6,25E-6,2.5E-6 9860,9860,9860,0 ;mask name spw,+,-,sdv dk,+,-,sdv toc,+,-,sdv tos,+,-,sdv mask POLY 1300,1350,1250,15 3.0,3.0,3.0,0 10E-6,10E-6,10E-6,0 40E-6,40E-6,40E-6,0 ******************** build data input done ******************** ******************** the actual build ******************** ;job number job 100789 ;build name www hhh build XYZ 0.2945 0.215 ;signal name layer_name area signal ELF_17um L1 0.01077 ;preg name preg ISOLA_1080 preg ISOLA_1080 signal ELF_35um L2 0.0059 ;core name core ISOLA_3X7628 ;plane name layer_name area plane ELF_35um P1 0.05944 preg ISOLA_1080 preg ISOLA_1080 plane ELF_35um P2 0.05916 core ISOLA_3X7628 signal ELF_35um L3 0.00021 preg ISOLA_1080 preg ISOLA_1080 signal ELF_35um L4 0.01183 ;mask name area mask POLY 0.075 mask POLY 0.075 ;plate name top_area bottom_area perimeter plate OUTER 0.01077 0.01183 3.701 ;hole area hole 0.00113 ******************** the actual build done ******************** ******************** dimensional analysis ******************** ;end, start the analysis *** STARTING BUILDUP for job 100789 *** ***************** build summary for XYZ6 ***************** mean max min sdev preg weight: 5.09E-02 | 5.33E-02 | 4.88E-02 | 6.40E-04 core weight: 1.22E-01 | 1.26E-01 | 1.18E-01 | 1.16E-03 foil weight: 4.33E-02 | 4.76E-02 | 3.90E-02 | 1.28E-03 plate weight: 9.83E-03 | 1.25E-02 | 7.44E-03 | 7.17E-04 ----------------------------------------- total weight: 2.27E-01 | 2.33E-01 | 2.19E-01 | 2.00E-03 preg thick: 5.12E-04 | 5.41E-04 | 4.88E-04 | 7.64E-06 core thick: 1.02E-03 | 1.07E-03 | 9.68E-04 | 1.40E-05 foil thick: 6.26E-05 | 7.01E-05 | 5.57E-05 | 2.16E-06 ----------------------------------------- final thick.: 1.59E-03 | 1.66E-03 | 1.53E-03 | 1.60E-05 ********************* end of example *********************** ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. 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