George Kovatchev Sitius Automation SITIU S Why Use the UG Model for Dimensional Control UG Users Group Conference Fall 2000

About us Sitius Automation develops process oriented solutions that are fully integrated in commercial CAD systems We are Unigraphics Alliance Partner We specialize in dimensional metrology SITIU S

Who needs CMM inspection Die designer – verify the tool against the part NC programmer / CNC operator – improve the cutting process Tooling engineer – make corrections to compensate for casting deformations QC manager – conform to company standards Production technologist – maintain stable process Assembly group – save time fitting CMM operator – overtime, teach the engineers GD&T The boss – keep the customer happy INSURANCE SITIU S

Preventive and Corrective Use Identify cutter deflection SITIU S Best-fit EDM electrodes Correct casting locators

How it’s done SITIU S Geometry 3D Cad Model2D Drawings CMM ProgramManualCMM ProgramPart Verification

How 2D compares to 3D (+) No need to buy new CMM software (-) Very difficult to inspect free-form surfaces (-) Need to maintain 2D drawings (-) Low reproducibility (-) Increased chance of errors (-) Hard to keep up with engineering changes SITIU S

How manual inspection compares to off-line programming (+) Highly adaptive –changes in setup –missing features –on-the-floor inspection –changes in requirements (+) Faster turnaround on low volume –tooling, inserts –EDM electrodes –prototyping –first article inspection SITIU S

How manual inspection compares to off-line programming (+) Works with manual machines –CMM’s –Laser trackers –Articulating arms (+) Easier to perform (-) Increased chance of errors* (-) Reduced repeatability and reproducibility* (-) Requires operator (-) Higher demand for CAD based solutions SITIU S

2D vs. 3D SITIU S From 2D drawings - 3 days To CAD model - 4 hours To CAD model - 30 minutes From 2D drawings - never

2D Drawings vs. 3D CAD Models Faster - sometimes by order of magnitude Inspect any part Increased repeatability and reproducibility Reduced data duplication Better way to inspect mechanical parts regardless of the method (manual or off-line programming) SITIU S

Are all CAD based inspections equal? NO Access to the math data Integration between CAD/CAM/Inspection Accuracy, performance and usability Other factors SITIU S

Comparison by interface to CAD IGES, VDA-FS, STEP, DXF –Most of the commercial systems use IGES Parasolid –Maybe one Direct links –Some promise, none really work Integrated –Two for Unigraphics SITIU S

Time to start work IGES - from 5 min to 5 days Parasolid - from 5 to 20 min Direct link - should be fast Integrated - from 1 to 2 min SITIU S

Accuracy and reliability IGES - low Parasolid - high Direct link - depends if there is a translation Integrated - 100% SITIU S

Example of IGES translation SITIU S Nominal points generated by the “industry leader” in CAD based inspection are compared with the actual Unigraphics CAD model. The CMM software uses IGES to translate the part. The profile tolerance is mm (actual part needs to be between the red and the blue line). In effect the nominal hits are off from mm up to mm, well below the lower tolerance limit of mm resulting in significant errors and repeated rework on the part.

Back to Unigraphics SITIU S The same part checked in Unigraphics before and after best fit.

Waste of time Source of errors Engineering changes Concurrent engineering Avoiding data duplication - is it important? SITIU S

2D Drawings - Yes IGES - Yes Parasolid - Yes Direct link - Usually Integrated - No if using User Defined Objects (UDO) Data duplication SITIU S

Access to solid information - very important for part verification and probe radius compensation Support for assemblies Graphical reporting and simulation Support for embedded GD&T Smart updates Macros, Parameters, Undo Other benefits of using an integrated solution for CAD based inspection SITIU S

CAD based simulation SITIU S

Reporting SITIU S Actual color-coded results GD&T reporting

Updates SITIU S

Summary Ability to work in 3D Accuracy and reliability Notification of changes Eliminate data duplication Concurrent engineering

Do yourself a favor If you design your part in Unigraphics inspect it there as well. This is your last step before you ship the part out. Do it right!

Thank you! on the web at Contact Us... SITIU S Please join us for a demonstration. SITIU S