about Nadcap Preparations with Scanbox system

[[ca...]]

Hello everyone,

We are preparing NADCAP accreditation for our ATOS Scanbox 5120 system. I am currently working on the white paper that GOM provided us. However, i still have some questions about asset care process including: how to perform balancing of lenses and how to check visual quality of projector. Could you please provide more info about these subjects?

 Secondly, in every step software checks itself by using its own KPI's, from measuring setup to photogrammetry to scan and some internal checks also applied in inspection side, too. My question is that if it is asked,  how can we access  some limit values or KPI's the system set for itself to consider whether the operation is successful or not. 

Thanks in advance,

Canset

[[Ch...]]

Hi Canset,

Here is a link to the ATOS 5 User Manual available in the GOM Library : https://library.gom.com/general/#tab=search&search-text=atos 5&search-info-271=10138%2C1&details=349.  Section 9 describes the Sensor Setup process.  The software provides a very nice guided workflow for lens adjustment.  

The user manuals for the other supported ATOS sensors can also be found in the GOM Library.

Many of the most important KPI's are set by the user - see Scan Point Computation Parameters in the Scanning Template and associated with each measurement and measurement series.  The limit values of some KPI's are relative.  Examples of this are the scale bar deviation in a Tritop/ATOS Plus measurement and the Fine Alignment residual ratio/s.  Since the ATOS software has to support the full range of applications, from low-end scanning to very high-end metrology for critical parts (teddy bears to turbine blades), for the highest levels of process control, it may be appropriate to establish local/specific KPI limits based on the values achieved during the MSA when the process was established.  Please can you tell us which KPI's you are using today to monitor your ScanBox processes?

Best wishes,

Chris

 

[[ca...]]

Hello Chris,

Many thanks for your response. I reached and read the related documents about sensor set up.We are currently using ATOS 5 Airfoil sensor head.

We change the acquisition parameters(resolution,quality etc.) depending on the part geometry to be scanned. Furthermore, in terms of scan point computation, we always make sure that movement check and light check are set before scanning. I don't know anything about Fine Alignment residual ratio/s, could you please explain more about it?

I am also wondering that are there any parameters(KPI's) that the system uses to check the process  in itself and it is not allowed to adjust by the user in terms of photogrammetry and scan?

Many Thanks,

Canset

 

[[Ch...]]

Hello Canset,

Sorry for the delay in replying to you.

We have a FAQ (frequently asked questions) article on the topic of Project Residuals but I'm not sure if everyone has access to it - https://connect.gom.com/display/GKB/Project+Residuals - I have attached a PDF of the article just in case.

The article explains the three Fine Alignment residual values that are reported for a measurement series.  'Residual', 'Preview Mesh Residual' and 'Reference Point Residual'.  In addition to these three values, ATOS also monitors the ratio between the 'Preview Mesh Residual' and 'Reference Point Residual'.  This ratio has a threshold of 4.0, meaning that ATOS reports a warning if the ratio between these two parameters exceeds 4.0.  This ratio is tested for both cases,  Preview Mesh Residual:Reference Point Residual and Reference Point Residual:Preview Mesh Residual.

There will be other parameters which the software uses to calculate/assess results but which are not exposed to users.  I guess this is the case for all complex software.  I guess these parameters are well understood by GOM and can be correctly set by the software. In my experience, by following the defined workflows, the parameters and KPI's exposed in the user interface give me all the controls I need to create capable and reliable processes.

I hope this helps.

Best wishes,

Chris

GKB-ProjectResiduals-310122-0924-1030.pdf

Edited January 31, 2022

[[ca...]]

Hi Chris,

Many thanks for detailed explanations and documents. I have one more question about thermal compansation mechanism that the ATOS system uses.

According to the NADCAP  requirements, we also need  to have some knowledge about thermal compensation mechanism that system uses. In another way of saying, we need to  verify that the project template(or script) we use for   acceptance test is complied with VDI VDE 2634 part 3 requirements. Is there also a document that you can provide us to verify that information?

Best wishes,

Canset

[[Ch...]]

Hi Canset,

Sorry for the delay again.  My notifications don't seem to be working on this page.  I have changed my settings and hopefully I will get an email notification the next time you post and I will reply sooner.

I'm sorry but I'm not sure that I understand your last question.  Would it be possible for you to post the specific section of the NADCAP requirements to which you are referring?  Alternatively, would you like to have a telephone/video call?  Perhaps I can help you more directly and quickly this way.

Cheers for now,

Chris

c.simmons@gom.com

[[ca...]]

Hi Chris, 

We solved the problem with PTB and NIST certificates. Thanks for the quick response.

I have another question about photogrammetry measuring volume. Do we also need to perform acceptance test according to 2634 part 1 requirements and if required then what should be the calibration frequency and what should be the type of required artefact type (GOM PSA 400 etc. )?

Many thanks,

Canset

[[Ch...]]

Hi Canset,

That's a good question.

GOM perform an acceptance tests according to VDI/VDE 2634 Part 1 for ATOS Plus and Tritop systems prior to delivery.  I'm not sure if the manual describing how to perform this process is available to customers but, assuming it is, below is the link to it in the GOM Library. 

https://library.gom.com/main/nova-app/explore(dialog:detail;id=846_asset;tab=metadata)?asset=846_asset

The GOM acceptance test for ATOS Plus and Tritop systems uses a special aftefact made of a number of DAkkS certified scale bars with multiple lengths arranged within a cube shaped frame.  There are different sized cubes and scale bars for groups of photogrammetry measuring volumes.

I don't think it is common (if at all) for customers to have their own artefact for performing this acceptance test themselves.  It is possible to arrange a periodic service and verification of your ATOS Plus system via either your local supplier or the GOM Service department.

It is important to maintain the scale bars/rings used in your ATOS Plus/Tritop processes.  These should be re-calibrated on a periodic basis as defined in your quality system.

I would also suggest a periodic review of the condition of your reference frames.  At a basic level, this means checking the condition of reference points and replacing any which are damaged.  Also, check for general wear, especially anything which could affect the stability of the reference frame and/or fixture.  I also recommend performing  a periodic analysis/Inspection of the stability of your reference frames over time, using a photogrammetry stage project.  This is especially important for processes which have relatively long cycle times, such as for blisk measurement.

I hope you find this helpful.

Cheers for now,

Chris