Research On Vehicle Headlampassembly Porocess Based Self Adaptive Variation Compensation

The dimensional quality of vehicle assembly has been one of the most important factors to represent manufacturing capability. The 3D Assembly variation model can predict assembly quality effectively, identify potential assembly variation resource and optimize enablers by both assembly structure and process design. Vehicle Headlamp's assembly variation control is one of the most difficult problems for vehicle dimension quality. The key point is robust process design to compensate assembly variation due to many enablers related to special product structure, part quality, assembly adjustment process which are difficult to control. Assembly variation research on key areas around headlamp not only helps process design among exterior parts, but also is worth studying and referring to for the whole vehicle assembly dimension control.The paper analyzes one kind of headlamp's styling package for typical assembly structure by collecting and comparing various models and thus to summarize advantage and disadvantage among different structures, improving fitting quality around headlamp in Shanghai GM face off program from structures optimization proposed based on dimensional issues from current model. It proposes Headlamp assembly's self adaptive variation compensation method, to create 3D model, and compare actual measurement data so as to establish improving solutions and apply to manufacturing.The study deploys from following aspects:1. Self adaptive variation compensation design of headlamp assembly structure. The method is introduced aiming to combined assembly between rigid and flexible parts. On the basis of dimension chain spread theory study, variation breakdown on matching surfaces is proposed to create headlamp to fender and hood assembly structure. Utilizing adjustable nut and characteristic of fender flexible assembly to set up compensation step and initial optimized structures.2. Headlamp assembly variation model and process optimization. To simulate variation analysis and theoretical validation by using 3DCS and NASTRAN software. The purposes are: (1) Simulate assembly variation between headlamp and fender, between headlamp and hood by new structures. To verify the structures is useful compared with old design. (2) Simulate rigid displacement of headlamp assembly for fender self-adaptive compensation input for further optimization at the fender installation interface. (3) Verify feasibility of self-adaptive compensation structure.3. To collect measurement data from sample vehicles and make comparison with design status and current model to prove the self adaptive variation compensation design effective.The paper proposes datum location evaluation index model to replace the usual datum location strategy oriented by experience, to particularly apply self-adaptive compensation method to vehicle headlamp assembly structure design combined with flexible sheet metal assembly character. The research directly improves products quality by optimizing fitting quality around headlamp.