rubber nozzle is necessary IMHO (saw failure before... the cavity  
inside is not very rigid to support over travel of metal/ceramic  
nozzle).   shock movement may cause cantilever to stick or deform.   
leveling the parts (if not very sensitive for application, it is ok)  
is pain.  some need internal calibration after the SMT process  
(embedded calibration, just need to do it  once - as  part of your  
final test procedure before  shipping - usually for high end  device,  
not consumer type).  fyi only.
old book.
jk
On Sep 20, 2018, at 1:03 PM, Steve Gregory wrote:

> Hi Larry,
>
> Did you have these little boards panelized? If so, how did you  
> singulate
> them?
>
> The customer's assembly notes contain a lot of the same Invensense  
> notes
> and also contain statements like: "IT IS SUGGESTED TO USE PLASTIC/ 
> RUBBER
> NOZZLES instead of using metal/ceramic pick and place nozzles.
> - SHARP AND SUDDEN IMPACTS should be AVOIDED.
> - The following Pick and Place parameters are recommended to  
> minimize the
> machine impact force on the MEMS device:
> a. MOUNTER TRANSFER MAX SPEED: 50cm/s
> b. MOUNTER MAX FORCE: 480GF or 4.7N
> C. AS A GOOD PRACTICE, SET UPH (Units Per Hour) OF SMT AS <60% OF IT'S
> DESIGNED SPEED. (example: Panasonic NM-EJMTD designed speed: 35.8k
> Units/Hour)" and: "PCBs that incorporate mounted sensors SHOULD NOT BE
> SEPARATED BY MANUALLY SNAPPING APART. This could also create g- 
> forces in
> excess of 10,000g. (Laser cut should be a good practice). Their  
> notes also
> contain a statement that manual soldering should be avoided.
>
> I can't find out how these InvenSense motion sensors are  
> constructed, but
> it's probably the same sort of construction that the IPhone motion  
> sensor
> is, which is a vibrating fork gyro, here's an IPhone 4 gyro:
>
> https://d3nevzfk7ii3be.cloudfront.net/igi/UurGsklhtJRW2uuB.huge
>
> Obviously there needs to be some pretty specialized processes set- 
> up when
> you are building boards with these motion sensors that I will need to
> account for in my labor quotes.
>
> Steve
>
>
> On Thu, Sep 20, 2018 at 9:37 AM Larry Dzaugis <[log in to unmask]>  
> wrote:
>
>> Assembled similar small boards.
>> Had 11" reeled components. Had to cushion any location where they  
>> were
>> stored on the side.
>> Had difficulty getting the factory to treat then as delicate parts.
>> All assemblies were trayed for handling.
>> It was a no clean process for automotive.
>>
>>
>> On Thu, Sep 20, 2018 at 11:26 AM Stadem, Richard D <
>> [log in to unmask]>
>> wrote:
>>
>>> I worked on the development of MEMS gyro components for Honeywell  
>>> and
>>> Benchmark 15 years ago. They are indeed extremely sensitive  
>>> components,
>>> measuring and controlling pitch, yaw, and thrust on avionics.  
>>> They are
>>> actually a miniature spinning gyroscope on a gantry, and the gantry
>>> measured the interial forces of the spinning gyro. We initially  
>>> had a
>> high
>>> fallout of these components but had great difficulty testing them at
>>> different stages of the process to determine where the shock/ 
>>> vibration
>> was
>>> occurring that caused them to fail. So I assembled a shock/vibration
>> reader
>>> to the output of the MEMS and attached it directly to the CCA,  
>>> which in
>>> turn transmitted a Bluetooth signal to a data receiver/recorder. I
>> tracked
>>> the shock/vibe on a sample of three parts from Honeywell's factory
>> through
>>> the delivery truck through all of the manufacturing processes. It  
>>> was
>> clear
>>> we were looking for a process that delivered steady-state or at  
>>> least
>>> re-curring vibration of such intensity that a sudden drop/upward  
>>> shock or
>>> huge thrust coupled with high inertial forces was causing the  
>>> failures,
>> as
>>> seen by 500x views of the damaged areas. The three samples  
>>> tracked very
>>> similarly throughout their life from fabrication through final
>>> assembly/inspection. I could only track one at a time, but all three
>>> recorded the greatest shock and either partial/intermittent  
>>> failure or
>> full
>>> failure after the in-line wash process. The cavitation of the  
>>> wash water
>>> sprayers caused all three to fail, and were the greatest shock/ 
>>> vibration
>>> readings in their short little lives. So we changed to a different
>> assembly
>>> process, putting the MEMS on after all other processes were  
>>> completed and
>>> used a manual wash process with full blow-off and a short bake  
>>> for 15
>>> minutes at 105 C.
>>> No more failures.
>>> Changes were made to the physical design of the MEMS at that  
>>> time, and
>> for
>>> all I know that could be the component you are dealing with  
>>> today. Or it
>>> may be something entirely different. But I do know this; the wash  
>>> process
>>> can be very destructive on MEMS components for the reasons stated  
>>> above.
>>> Odin
>>>
>>> -----Original Message-----
>>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
>>> Sent: Thursday, September 20, 2018 9:18 AM
>>> To: [log in to unmask]
>>> Subject: [TN] 6-axis MEMS Gyroscope/Accelerometer assembly
>>>
>>> Good morning everyone,
>>>
>>> We're quoting this little 1.5" X 2.5" assembly that has a TDK/ 
>>> InvenSense
>>> 6-axis MEMS Gyroscope/Accelerometer on it (PN# ICM-20648). I've not
>>> assembled a board with one of these devices on it before. When I  
>>> read the
>>> datasheet, and then the handling guidelines for these parts (
>>>
>>>
>> http://www.invensense.com/wp-content/uploads/2015/02/InvenSense- 
>> MEMS-Handling.pdf
>>> ) I was quite surprised how fragile these things are seeing how  
>>> they are
>>> primarily used on wearable devices where they are going to see a  
>>> lot of
>>> shock. Yeah I know it is a MEMS part, but it would seem to me if  
>>> it can
>>> survive all the abuse it will see being in a wearable device that it
>> would
>>> be a little more robust during assembly.
>>>
>>> So have any of you who have placed these sort of devices, have to  
>>> make a
>>> bunch of changes in their standard assembly processes and stockroom
>>> handling practices to accommodate these parts?
>>>
>>> Thanks in advance,
>>>
>>> Steve
>>> --
>>> Steve Gregory
>>> Kimco Design and Manufacturing
>>> Process Engineer
>>> (208) 322-0500 Ext. -3133
>>>
>>> --
>>>
>>>
>>>
>>> This email and any attachments are only
>>> for use by the intended
>>> recipient(s) and may contain legally privileged,
>>>  confidential, proprietary
>>> or otherwise private information. Any
>>> unauthorized use, reproduction,
>>> dissemination, distribution or other
>>> disclosure of the contents of this
>>> e-mail or its attachments is strictly
>>>  prohibited. If you have received
>>> this email in error, please notify the
>>>  sender immediately and delete the
>>> original.
>>>
>>
>
>
> -- 
> Steve Gregory
> Kimco Design and Manufacturing
> Process Engineer
> (208) 322-0500 Ext. -3133
>
> -- 
>
>
>
> This email and any attachments are only
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> recipient(s) and may contain legally privileged,
>  confidential, proprietary
> or otherwise private information. Any
> unauthorized use, reproduction,
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