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  1. Joshmo

    Apparently, not your typical TITLE BLOCK question...

    We had a similar occurence which we got through our system by using their titleblock and part numbers with their own sign off area and seperate area for our sign off. Our sign off region said "Designed by Our Company" and was just added on the left side of our customers main titleblock region...
  2. Joshmo

    Elevated Temperature Tolerances!

    I would scale the part in a CAD system by (1-(alpha x delta T)) where alpha is the CTE. The desired tolerances should be the same as needed but the nominal size would be scaled using this technique.
  3. Joshmo

    Outsourcing stage 3 - Design Tasks

    My two cents being previously a design contract engineer working on outsourced projects is the following: * You must have the design requirements fully spelled out(Tolerances, materials, ICD's, environments, weight, finishes, pressures, dynamic/random vib, etc...) * You must require the...
  4. Joshmo

    fire in our autoclave. Why?

    When curing large quantities of partiuclar resins they can exotherm but I don't think they would actually catch on fire. I think such exotherming is associated with cyanate esters and perhaps bmi's, not epoxies.
  5. Joshmo

    Sealing carbon fiber tubes for deep water application

    How about bonding a fitting on the end and have it contain what ever cap seal you need? With a single lap bonded joint have the composite on the inside so that during a pressure load case the composite can't peel away from the fitting. Also Suggest using an aerospace grade structural adhesive...
  6. Joshmo

    Carbon fiber reinforced carbon with LOW thermal conductivity

    Spinda, at 1000 deg C tradtional composite materials will not work. Even more advanced resin systems such as polyimide or BMI have Tg's of only 400 Deg C. But, you may be able to use Carbon-Carbon composites which have the resin burned off and infiltrated with carbon. C-C can maintain strengths...
  7. Joshmo

    Auxilliary Section View Question

    ctopher, thanks for the response but I guess my question is more related to view creation fundamentals rather than the particular drawing I have shown. The drawing I have shown is just an example where I am really interested in knowing whether its acceptable to have projected views not at the...
  8. Joshmo

    Auxilliary Section View Question

    All, this is a simple question so I'm sure it won't strain anyone's brain. I had a discussion with someone at my work this morning about making an auxilliary view not being at the correct projected angle just to make the drawing look nicer. For the case that a tradtional auxilliary view won't...
  9. Joshmo

    Phenolic/Foam issue

    Tapirg, From my experience I would recomend using alot more pressure during the cure to evacuate the higher level of volatiles associated with phenolic resin. I would say at least 60 psi would be necessary assuming that this much pressure doesn't damage the foam. Josh
  10. Joshmo

    Stiffness and strength of Panels for a camera crane arm

    We are pretty close to you in San Diego and could easily engineer/test such a structure: Josh Moore jmoore@sdcomposites.com San Diego Composites, Inc. http://www.sdcomposites.com
  11. Joshmo

    Metric title block tolerances

    All, My only comment regarding metric default tolerances is that going to 3 decimal places in metric is almost useless since .001 mm is .00004" !!! JMo
  12. Joshmo

    Finding Equivalent Isotropic Properties for Composite Material

    David, download this Laminator program which uses laminate theory to make smeared properties from lamina properties: http://www.thelaminator.net/ Josh.
  13. Joshmo

    "Never spend more than 5-7 years in any job"

    I don't think anyone mentioned this...Changing jobs frequently may increase one's pay too much. If someone gets around 20% raise every time they change jobs, this may cause their pay requirements to be too high for the kind of work they do, thus causing them to be a less desirable employee. Who...
  14. Joshmo

    RSS correction factor for tolerance stack-up analysis

    ...tolerance stack. But, a customer recomended I use a modified correction factor instead of the 1.5 times the RSS using the following equation: {.5*(RSS-WC)/[RSS*SQRT(# of dimensions)-1]}+1 where RSS is the root square mean of tolerance stack-up and WC is the worst case tolerance stack. The...
  15. Joshmo

    Changing Part units in NX5

    Hello all, I am a new NX5 user and ran into a problem I would think would be simple to figure out but got a little stumped. I made a part in mm but later wanted to swith it and all the dimensions to inches. The only way I found to do this was by using the NX command prompt and typing...
  16. Joshmo

    Outgassing of Silver Oxide, Copper Oxide, or Cusil in Vacuum

    NASA has an extensive outgassing database online: http://outgassing.nasa.gov/ Not sure it covers exactly what you are looking for but its worth checking out. Hope this helps,
  17. Joshmo

    carbon fiber and aluminium

    This is off topic from your questions but some applications of composites used in optical structures require low outgassing resins to avoid organics depositing on lenses or mirrors during the structures service life. This might not be a requirement but something I have encountered before but...
  18. Joshmo

    carbon fiber and aluminium

    Can you use fasteners with slots in the direction of thermal growth? If the load direction isn't in the same direction as the slots this could be a viable solution.
  19. Joshmo

    carbon fiber and aluminium

    Etch and prime the aluminum for repeatable bond strength. Typical acid etching works with a BR-127 primer. Additionally, another benefit of this method is that the aluminum part can be treated then stored for use versus sand blasting or hand abrading which requires bonding within 8 hours...
  20. Joshmo

    Assembly Drawing BOM Change Question

    Yes I'm using non-intelligent software so deleting the text from the item row is probally the best thing to do. I've drawn a line through the text before but deleting the text seems like a better thing to do. Thanks Guys!!!

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