Talk:Airsoft gun

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Revision as of 11:37, 12 October 2007

We received your report, and you have some interesting results. Typically we expect more findings and conclusions to be summarized in the executive summary - we need clear conclusions to work with, and it is difficult to dig for them. Overall, the detailed documentation of components is impressive, although it would be helpful to have more professional documentation introducing each section and helping the report to flow. Detailed comments follow:

• One major customer need is to emulate an actual gun - which attributes are important in this regard?
  • The appearance is typically the most important attribute that users will look for. The most common airsoft guns are automatic electric guns (AEGs), which are powered by a motor that drives a gearbox. Because many guns are approximately the same shape, in terms of having a handle and a trigger, though a few have variations, most gearboxes are about the same shape, and for the different variants of guns, the new gearbox can be made to fit. Gearboxes generally all function the same way, and their power and durability relies on the internal components, like what material the gears are made of or how strong the spring is. Because of this, the determining factor for airsoft guns is generally what "real steel" gun it is modeled after. Another common attribute, though not as important, is usually the weight or "feel" of the gun. People will buy airsoft guns sometimes to have the feel of holding and shooting something that looks like a real rifle, while not needing a gun licence.
• The description of functionality is quite clear, but it would help to include a figure with labeled components
• You mention child users - please discuss this further and address safety issues.
• Stakeholders - you mentioned crime as an issue, does this imply additional stakeholders?
• Nice bill of materials, but you do not show how all of these parts fit together, other than the trigger assembly. It is not obvious just from the list.
• It is difficult to tell from the pictures, but you might reconsider that some parts that have constant thickness but a bent shape may be produced through forging / stamping / bending rather than casting.
  • Some of the manufacturing processes have been changed, but for some of the parts, there is a seam around the part, which indicates it may have been cast. Parts like the safety switch, (T 01) have sharp corners at the bends that seem to indicate that the part was not bent or stamped.
• The manufacturing term for “lathing” is turning
  • Parts with this manufacturing process have been corrected.
• Reaming may be necessary for the barrel - you might consider
  • While we are not completely sure what method was used for producing this particular barrel, the process shown at the following site, http://www.madbullairsoft.com/English/index.php?main_page=product_info&cPath=7&products_id=44, is one method for producing barrels with a precise inner diameter. Reaming may or may not be the process used also due to the length of the barrel. It would need to be very accurate, since tolerances on airsoft barrels tend to be tight, ranging from very "tight" 6.01 mm inner diameter to wider 6.14 mm inner diameters. The barrel would also need to be very straight in order to get this accuracy, since either the reamer or the barrel must be turned and any bends or deviations may cause the inner barrel to not be accurate.
• Please provide an introduction to each section rather than beginning with a table of data.
• You mention in the FMEA that one of the most likely failure modes is fatigue of the spring from users storing the gun cocked. A users manual warning is okay, but we know from experience that this will not do the trick for most users. Is there another way to avoid this failure mode?
• LCA - you did not discuss major sources of GHG, pollutants, dominant life cycle phase, etc. Should we be worried more about manufacturing of the gun or of the BBs?
• DFMA is a nice list, but more detail and supporting information would be helpful
• Can you justify why the trigger mechanism is so complex? It appears that the same function could be performed with a single spring, since the only output is to move the lever out of the way of the piston release.
  • The trigger mechanism is complex due to the built in safety features. There are three mechanical safeties that prevent the trigger from accidentally being pulled. One safety, the safety switch (part T 01), slides into a position where it blocks the lever (part T 12) and prevents it from rotating, thus preventing the gun from firing. Another safety is the bolt safety, which prevents the gun from firing when the bolt handle is not rotated downward. There is a groove in the bolt assembly that lines up and when out of position, pushes the bolt safety (part T 14) down, which in turn pushes the bolt safety lock (part T 16) into a position where the lever is blocked and cannot rotate, thus preventing the gun from firing. The final safety is just the double trigger. The smaller trigger must be pulled in order to allow the primary trigger to be pulled, allowing the gun to shoot.
• In your calculations it looks like you measured spring constants by attaching known weights and measuring deflection? Please explain what you are doing, otherwise we cannot follow where the equations and numbers are coming from.
• Your final result is that the force required to pull the trigger is 2.5 N based on experiment, but your calculations seem to show 1.72. Please explain the discrepancy. Also, what does this result tell us? Is this force too high? Just right?