# Machine Capability Analysis in Multi-Dimensional Cases

I

#### isbalanli

Hi everybody
As a newcomer I have the question about machine capability analysis.

1) We have 4 CNC machines. Then we machining one reference part (reference part means: all parts have the same shape), three times in each machine. This meeans that we have 12 machined parts. [cosider a 12x500 table]

2) Then we measure all 12 parts with CMM. As measured points, we have 500 points in each part. (we have the CAD model. This means that for all points we have the nominal value.)

The question is:
How to calculate the capability of each machine?
How to compare the machine's performances?

T

#### tbsiva

As I dont have experience in CNC machining, I will try to explain the answer with an example from injection moulding. I am not sure whether my answer will help you.

Even in my case, a injection moulding part has 100 dimensions. To calculate the machine capability, we need to produce 50 samples. So, I need to measure 50 X 100 = 5000 dimensions/machine. We have 50 machines. So, to calculate machine capability for 50 machines, it will be 5000X50 machines = 250000 dimensions, which is practically impossible.

What we have done is we have decided to measure the part weight, because consistency in part weight is the parameter which defines the performance of the machine. That means we have converted 250000 dimensions into 1 X 50 X 50 = 2500 measurements of weight, which is a much simpler and effective process

Coming back to your concern, Is it possible to define one or two parameters which is the most vital parameter that will effectively say that my machine is capable or not? If yes, identify those parameters and conduct capability study for those charateristics alone.

I

#### isbalanli

As I dont have experience in CNC machining, I will try to explain the answer with an example from injection moulding. I am not sure whether my answer will help you.

Even in my case, a injection moulding part has 100 dimensions. To calculate the machine capability, we need to produce 50 samples. So, I need to measure 50 X 100 = 5000 dimensions/machine. We have 50 machines. So, to calculate machine capability for 50 machines, it will be 5000X50 machines = 250000 dimensions, which is practically impossible.

What we have done is we have decided to measure the part weight, because consistency in part weight is the parameter which defines the performance of the machine. That means we have converted 250000 dimensions into 1 X 50 X 50 = 2500 measurements of weight, which is a much simpler and effective process

Coming back to your concern, Is it possible to define one or two parameters which is the most vital parameter that will effectively say that my machine is capable or not? If yes, identify those parameters and conduct capability study for those charateristics alone.
Thanks for answer. Good idea. But the problem is that, when I talk about dimension, they are scanned parts. So I have 500 point cloud for each part. Reverse engineering and making CAD model to calculate the weight is so time consuming process. (also sampeled points are not dense enough to lead the accurate answer) .Of course I have calculated the differences between all nominal (CAD) and real (scanned) parts. (bofore I had [x,y,z,i,j,k] for each point and I calculated the differences for obtaining the scalar number instead of torsors with 6 elements).

Machine Capability Capability, Accuracy and Stability - Processes, Machines, etc. 2
Machine Setup for a CNC Machine Capability Study Capability, Accuracy and Stability - Processes, Machines, etc. 1
A Statistic Tools to Know Capability of Sealing Machine for Seal Width Capability, Accuracy and Stability - Processes, Machines, etc. 3
Proving Process Capability of a Packing Machine Capability, Accuracy and Stability - Processes, Machines, etc. 6
B Determing Machine Capability in a High Mix, Low Volume Sheet Metal Shop Manufacturing and Related Processes 4
S What is the difference between Process Capability and Machine Capabilty Capability, Accuracy and Stability - Processes, Machines, etc. 13
F Capability for a Injection Mold Machine (35 Cavities) Capability, Accuracy and Stability - Processes, Machines, etc. 17
L Capability studies on machine types - Supplier has over 1000 machines Quality Manager and Management Related Issues 7
L Capability Study for a Honing Machine Statistical Analysis Tools, Techniques and SPC 3
G How to calculate Subgroup Size for Machine Capability Study Statistical Analysis Tools, Techniques and SPC 4
V How to calculate Machine Capability Study using Minitab Using Minitab Software 4
A CQE Exam Machine Capability Question - HELP Capability, Accuracy and Stability - Processes, Machines, etc. 7
K Excel Spreadsheet Template to calculate Cmk (Machine Capability) wanted Capability, Accuracy and Stability - Processes, Machines, etc. 2
Machine Capability (Cm) for Plastic Injection Molding Capability, Accuracy and Stability - Processes, Machines, etc. 1
Machine Capability with Plastic Producers Capability, Accuracy and Stability - Processes, Machines, etc. 1
Q Machine Capability Study - Cpk (Cmk) of an R/F testing machine Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
R How to measure Machine Capability index Cpm Statistical Analysis Tools, Techniques and SPC 1
T Machine GR&R (Gage R&R) - Capability Study Capability, Accuracy and Stability - Processes, Machines, etc. 5
M Cmk (Machine Capability) - Case study Capability, Accuracy and Stability - Processes, Machines, etc. 5
M Machine Tool Calibration - Machine Capability Studies on CNC Machine Tools Manufacturing and Related Processes 5
M Volumetric Positioning - Machine capability studies for CNC machine tools General Measurement Device and Calibration Topics 4
I Reason for pre-production machine/process capability studies / SPC during production Capability, Accuracy and Stability - Processes, Machines, etc. 3
V Machine short term capability study with Cmk index in automotive industry Capability, Accuracy and Stability - Processes, Machines, etc. 3
Y Product Stability (Machine Capability) vs. Equipment Repeatability (Gage R&R) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
S Machine Capability vs. Process Capability - Differences? Capability, Accuracy and Stability - Processes, Machines, etc. 16
M Differences between Machine Capability and Product Capability studies Capability, Accuracy and Stability - Processes, Machines, etc. 9
Q Confused about the machine capability index Cmk Capability, Accuracy and Stability - Processes, Machines, etc. 1
M Is a machine capability the right thing to do Next? Laser measuring machine Capability, Accuracy and Stability - Processes, Machines, etc. 1
S Experience with DOE in machine capability study Capability, Accuracy and Stability - Processes, Machines, etc. 8
M What are the general rules / guidelines when doing a machine capability study? Statistical Analysis Tools, Techniques and SPC 9
A Acceptance criteria for Cmk (machine capability index) Statistical Analysis Tools, Techniques and SPC 3
M How To Conduct Machine Capability Of An Electrical Discharge Machining (edm)? Statistical Analysis Tools, Techniques and SPC 3
M How to Conduct a Machine Capability (Cmk) Study Statistical Analysis Tools, Techniques and SPC 27
S Cmk and Cpk - When will we need to calculate Cmk? Machine Capability Capability, Accuracy and Stability - Processes, Machines, etc. 4
Machine Capability Studies on CNC Lathes Statistical Analysis Tools, Techniques and SPC 35
S Cmk is defined as a Capability Index for a Stable Machine Capability, Accuracy and Stability - Processes, Machines, etc. 8
D Machine Capability Studies: How many parts needed? Statistical Analysis Tools, Techniques and SPC 11
S How to determine a machine capability? Measuring results for only one shaft APQP and PPAP 1
S How to Determine a Machine Capability? Shaft Fit Tolerance Measurement Results Statistical Analysis Tools, Techniques and SPC 2
M Determining Machine Capability and Process Capability of a Shaft Statistical Analysis Tools, Techniques and SPC 1
D Where can I find Process & Machine Capability study software? Statistical Analysis Tools, Techniques and SPC 3
Traceability after changing the machine IATF 16949 - Automotive Quality Systems Standard 13
Screen printing ink and machine selection_ Need help Manufacturing and Related Processes 6
Minimum Distance from Floor to Underneath of Machine Human Factors and Ergonomics in Engineering 3
PMA vs 510(k) for Mammography Machine US Food and Drug Administration (FDA) 2
Tensile test machine, tinius olsen 602 Manufacturing and Related Processes 1
Class II type machine , and its compliance with 60601-1 IEC 60601 - Medical Electrical Equipment Safety Standards Series 14
SOP for CNC turret punching machine for sheet metal process Manufacturing and Related Processes 0
Any ISO standards around Artificial Intelligence and Machine Learning? Medical Information Technology, Medical Software and Health Informatics 4
Software Validation for FFS Packaging Machine Qualification and Validation (including 21 CFR Part 11) 1