The starting point
Nori had a broken roller blind from the centre console of a Mercedes W166 / X166 / C292 (OEM part 1666803814). The original is a chain of hinged slats whose end pins ride in a groove on each side of the console. Its thin, rubbery hinge web was destroyed by heat and the slats came apart.
The project started from ten photos of the broken part, taken with a ruler, a caliper and a printed checkerboard, plus a listing photo of the complete part that we used to count the slats and compare the spacing of the pins.
The problem
The console track is closed. The original can only be fitted by removing the whole console. A replacement had to go in from above, into the closed track, and then stay put: a cup or a palm pressing on a slat must never push a pin back and drop the slat into the cup holder.
What we designed
- A parametric model. Every dimension lives in one parameters file. After a test print, only that file changes and the model, the validation checks and the exports are rebuilt. The build stops with an error if a size or clearance check fails.
- A spring-loaded pin on one end of each slat. The other end has fixed pins. The sprung pins are pulled back by hand with a pick or a fingernail, the slat is lowered into the track and released. We rejected a ramped pin that retracts when pushed down, because it would retract under a cup as well. Every pin face that carries load is round or flat.
- A knuckle hinge. Interleaved barrels on a 1.5 mm steel wire replace the rubbery web. The design allows 45 degrees of bend one way, against the 35 degrees needed for the track curve on the figures we had.
- A handle slat and a tail slat that follow the original layout, with the changes listed in the project notes: a wider slat top plate, recessed instead of raised dashes, and a wider handle end block.
- A fallback with no moving parts, where each slat is bowed by hand and dropped in, plus a bend-test slat.
- Print-ready outputs. STEP, STL and DXF files, a 3D preview that opens in the browser, and parts already oriented for the slicer.
How it is made and tested
Parts are meant to be printed in FDM, top face down. The notes record that PETG-CF is marginal at the roughly 80 degC a parked cabin can reach, and that ASA-CF or PA-CF is preferred.
Before printing the whole blind, three coupons are printed first: the end of a slat with its housing and sled, two hinge segments joined with a short wire, and a full slat for the fallback variant. They check the sliding fit, the press fits, the hinge clearance and the overhang quality.
SolidWorks version
We also started a native SolidWorks model, driven from Python, where every dimension is a global variable in one equations file so it can be re-tuned inside SolidWorks after a test print. Reviewing the first idea showed that a very thin hinge web would be strained about 16 times more than first estimated. The plan changed to a rigid strip with a wider, thin flex band, which the calculations put at about 2.4 to 3.0 percent strain instead of about 20 percent.
The first slat has been built. Its volume matches the hand estimate within 0.04 percent and its bounding box matches the expected size. Changing the groove depth in the equations file lengthened the pin-tip to pin-tip span from 219.4 mm to 221.4 mm, as intended.
Where it stands
Some key dimensions, such as the track width, groove depth and tightest curve, are placeholders until they are measured on the car. We have no test-print result to report yet, so this story ends where the work does: a validated model, print files, test coupons and a SolidWorks model under way.