Kidney Grille Support Ring...

[Z4Kevo]

Hello all,

I recently took a frontal impact from road debris and came away with a not too happy front bumper. I am in the proces of getting it worked on and the front bumper is an impossible thing to come by these days.

The bumper itself is in good condition albeit in need of a repaint. The catch is that the grille got punched out and the interior ring that holds it in place was shattered. Now grille no stay in place.

I had originally thought this interior ring was integral to the front bumper, but as it turns out it is a separate piece that is attached via plastic studs and held in place with catch tabs...see pic.

I checked RealOEM and it is not listed as a separate part as near as i can tell.
Does anybody know if this part can be had by itself and if so where?

Thanks gang...appreciate your input!

[Z4Kevo]

I am kicking around if there is a way I could take an existing grille (that I could sacrifice), coat the back of it in mold releasing agent and then do a fiber glass wrap and build up the negative image of the grille to be used as the grille ring.

...or find somebody who does or did produce aftermarket body work and get a custom ring from them should they being willing to oblige for a fee.

[pungo]

Could you use some hotmelt glue or butyl tape to hold it in place?

[Z4Kevo]

I am currently keeping the grille from falling out by using velcro in the few places left that I can attach it.

As far as patching the ring...unfortunately nothing can be done to hold it together. the section of ring in the pic is broken as you can see, but roughly half of the ring not shown in the picture is missing altogether. Scattered somewhere on a roadway.

[Steeler]

I sourced an absolutely destroyed bumper to replace the kidney support rings for my car.
AFAIK the support rings are identical for all non M and M's from 03-08.

The support ring is held in by tongues that are part of the bumper cover.
The support ring has slots that accept the tongues.
The tongues are melted/plastic welded from the backside of the support ring.

[Z4Kevo]

Originally Posted by Steeler

I sourced an absolutely destroyed bumper to replace the kidney support rings for my car.
AFAIK the support rings are identical for all non M and M's from 03-08.

The support ring is held in by tongues that are part of the bumper cover.
The support ring has slots that accept the tongues.
The tongues are melted/plastic welded from the backside of the support ring.

Thanks...on my to do list before i explore other routes.

[Z4Kevo]

I have decide to just remove the opposite side that is still good, 3d scan it, mirror it to the opposite hand and then 3d print up a new one.

[Steeler]

Originally Posted by Z4Kevo

I have decide to just remove the opposite side that is still good, 3d scan it, mirror it to the opposite hand and then 3d print up a new one.

Any interest in making a few sets?

I would buy if price is right.

[Z4Kevo]

Haha...Let me make a few that actually work first then we can talk!

I am currently working on refining the model in Rhino...basically reverse engineering it as much as it can be. The design of this part is quite sculpted in nature, so it can't simply be calipered like other geometric primitive based parts...making post-process CAD work VERY tedious...that oddly enough i find somewhat challenging and fun! The wife is baffled at my self toture.

Even with the almost impossible editability and smoothed out nature of 3D scans (even at 0.1 - 0.2mm resolution) there is something to be said for a resulting model that represents the ACTUAL geometry and positioning of critical features instead of a beautifully modeled part that is close, but still just an approximation.

Assuming I get the print to have enough structural strength with added reinforcing, infill and whatever extra bracing i can put in there I see no reason why it would not function in place of the original!

I will keep you guys posted.

FYI - I have been eyeballing the E83 Android upgrade for use in our E85/E86. I would like to take the dive into the upgrade, but have been worried about the dash trim not fitting up and what that would mean for cars with existing NAV. So, if the grille retaining ring works out I may explore the idea of 3D printing a new dash trim surround to suit that particular unit. Fingers crossed.

[Z4Kevo]

Slow but steady... 9 hours into the full test part. Will fine tune the supports for the next ABS nylon run...turns out the auto-support feature missed a critical support point and I did not catch it before i started this test run...so it is sagging at one point along the base a bit before it got to the next support leg. This print is just to test for dimensional accuracy across the entire part and to make sure that the grille actually snaps in place, so this blunder was not a show stopper.

Also something I ran into during the small test parts i ran...they were breaking at the flex tabs because the flex plane was parallel with the layer deposition. So...printing it at a 45 degree angle to minimize supports (facilitate faster cleanup...prettier part) and provide strength for the flex tabs. 90 deg would have been better but printing it standing on end had its' own issues.

[Z4Kevo]

Ran several prints using PLA, PETG and ABS. ABS is finicky stuff...multiple failures with bed adhesion, warping and stringing...but finally got it worked out, but have yet to print a full part with it. Ultimately though I will likely run with PETG. A bit more strength and flexiblility than PLA but not as "rubbery" or as tempermental as ABS.

Here are a few pics of the PETG version...Yes, it does look like a typical printed part and No i did not spend much time on "beauty" dressing the backside since it will not be seen...just removed the boogers to make sure I could achieve proper fitment. The holes, slots and feature alignment is spot on...the grille tabs work great...grilles snap in and out.

All-in-All i would say this is a win considering i would still be waiting for a front bumper with no arrival time in sight.

[Steeler]

Originally Posted by Z4Kevo

Ran several prints using PLA, PETG and ABS. ABS is finicky stuff...multiple failures with bed adhesion, warping and stringing...but finally got it worked out. Ultimately though I will likely run with PETG. A bit more strength and flexiblility than PLA but not as "rubbery" or as tempermental as ABS.

Here are a few pics of the PETG version...Yes, it does look like a typical printed part and No i did not spend much time on "beauty" dressing the backside since it will not be seen...just removed the boogers to make sure I could achieve proper fitment. The holes, slots and feature alignment is spot on...the grille tabs work great...grilles snap in and out.

All-in-All i would say this is a win considering i would still be waiting for a front bumper with no arrival time in sight.

Excellent work.

As stated before, if you are willing I am interested in a set, pending price point.
A new bumper cover is in my future and they do not come with these support frames.

Cheers.

[Z4Kevo]

Originally Posted by Steeler

Excellent work.

As stated before, if you are willing I am interested in a set, pending price point.
A new bumper cover is in my future and they do not come with these support frames.

Cheers.

I appreciate the enouragement and am certainly open to the idea of providing these to those who would like them!

My only sticking point thus far are the tabs and their strength. This concern is not exclusive to my 3d prints though...it also goes for the original rings too. When i removed the "good" ring to use as a template it had a broken tab that i super glued/baking soda'd back together prior to scanning..so even the original parts have this as a weak point. I can't solve it of course...so my real goal is to not make it worse.

My initial attempt at mitigtating this weakness by printing it at an angle (~60deg seemed like a good compromise) was a failure as I did not take into account the need to better design my support structure so they could stand as tall and straight as required for the print to eventually make it up to them.

I have since worked through that and am back at attempting another ~60deg angled print. Fingers crossed!

You might be asking why an angle? Attached is a pic showing two broken tabs. The one on the left was printed horizontally and the one on the right at ~60deg. The lines below show the orientation of the layering...the interface between these layers is an inherent weak point of the printing process.

When pressing the tab inward to engage the grille you can see that in the horizontal configuration you are flexing it axialy relative to the layer lines...it has quite a bit of strength and can take it for a while but it eventually snaps like in the pic. While testing for failure the one at ~60deg also broke along the same layer plane (in two places) in a way that took far more force than the horizontal version (roughly twice the material to resist). Better, but good enough? At what point is the potential for breakage considered to have been dealt with properly? Dunno.

This has been quite the learning curve especially when you throw in the different materials each with slightly different properties and printing requirements. If I can complete a full print with the finicky ABS (even though it feels a bit flexxy) it might actually be the best bet given my desire to mitigate the tab snapping...turns out flexxy is good! TPU is also a material i am looking into.

Whether or not I can ever produce a part that will consistently work as intended is the only thing holding me back from throwing this out there as a product for others to buy. I am not a professional 3d printer and would likely be called a hack by those who are...but i am learning (out of necessity) and would love to be able to provide something of use to others!

So I will keep plodding along, provide you guys with updates and God willing we can get there!

[Z4Kevo]

Behold the first angled print! That was fun...after a bit of setup time to prep the printing surface it took 36 hours to print and a sleepless night of monitoring its' progress.

This part is made out of PETG just like the previous horizontal print and everything about it in terms of how I had to prep it to receive the grille was almost identical, so that says something about the consistency of the print process itself...although these tabs are definitely stronger than they are on the horizontal one.

I removed all the printer supports (which is far easier on the angled print), deburred the print, sanded down the inner mating surface to help the grille to slide in and out smoothly, test fit and sanded until I was cross-eyed and finally coated it with an SEM satin black color coat. This took about an hour and a half to do, so not that bad.

For further peace of mind regarding the tabs I have ordered some two part liquid plastic weld epoxy to coat the backside of the tabs to help them resist any cracking or breaking. I don't want to hinder their flexibility though, so applying just the right amount will be crucial. I should be able to test that tomorrow when i get a free moment.

[Z4Kevo]

Messy, but the epoxy coating of the tabs went well (front and back side). Not sure that I want to break a part to test for strength seeing as how it takes so long to one of print these things up, but I can safely say that it certainly didn't hurt matters any! Fitment is still spot on.

Having suss'd out many of the issues with the nylon (bridging, curling, warping, bed adhesion), I am now printing up an ABS version to see how it compares to the others. It should be a bit more flexy and make the tabs more forgiving.

The bumper goes to the shop for refinishing today and I should get it back late next week. So i have about another week to sort out which ring I want to install as the working unit.

[Z4Kevo]

All back together again... pretty much like new. They even painted my reflectors!

[nwsnowboarder]

Bought my Z4M last year and my kidney grills are zip tied in because the tabs are broken. I would be interested in a set too.

[maupineda]

I would be too, issue with mine is the bumper cover tabs is what broke

[thrak410]

Amazing work!!

[Z4Kevo]

Thanks...appreciate the compliments.

A couple of caveats on the 3D model i generated for this.

It is essentially just a 3D scan that has been lightly cleaned and thickened in the modeler to make it printable. I didn't do any remodeling on it (like i did my dash trim piece)...consequently the model is accurate in all the dimensions it needs to be, but it is pretty dirty in the sense that triangular meshes derived directly from point clouds are not the cleanest.

But this was ok with me...i wanted an accurate part that i could rely on instead of one that i remodeled, cleaned up and introduced a certain amount of errors in the process. Since the part is buried and sandwiched between the bumper and other structures it was not going to be easily removed and replaced should anything go wrong with the part.

I had entertained the idea of printing these up for people who wanted them, but when you look at the cost of doing so it really wasn't something i ultimately wanted to pursue...and the price was not something that most would want to pay. So unless you absolutely need a set of these it is not something you would want to pony up the dough for.

The only thing that has stopped me from sharing the model with those that would like to print their own is the model quality. I guess this is kind of silly, but although the quality is fine with me in this application its not something i would provide to someone else unless they understood the reasons for the its crude nature and were OK with it.

So if any of you guys want to take a crack at printing them up and are OK with a dimensionally accurate model that is a bit dirty overall then I can make the .STL file available.