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NSX Door Liners and the troubles of injection molding

20 November 2016
Tokyo, Japan
If you haven't heard; MITA has been remaking the door liners. Similar but different than to what Billy Johnson was doing with his 3D printed version. We went with the direction of ABS Plastic Injection Molding. A huge investment but I think it was the only way to do it rather than 3D printing (to keep costs down and have a much more durable product).

We started the project back in June, we 3D scanned the door liners (all 3 pieces) and started doing 3D editing to them. If you're looking to do something similar, I strongly suggest investing in a really good scanner. We used a XBOX Kinect scanner at first but outsourced to a professional service to do it since the scans were not as good as what I personally wanted.

Luckily for me and the team at MITA, I have CAD experience from my uni days (many people do not know this). Expanding the tabs and reediting the panels was not difficult at all. (I wish I can upload photos but I'm not sure what is happening with Prime); so here is a google drive folder with all the photos:

We decided to be cheeky and add our own part numbers to the door liners like the OEM ones. Just in case anyone just needs to purchase a replacement. You can see it in the photos above.
So now time for the manufacturing process. And this is where the headache is. Before anything though, we 3D printed it suing Nylon to test fit the mounting points, and this was a success. We asked HQ Engineering in California (great guys there if you're in the area, you should check them out) to fit them and they fit like a glove. Though they did mention that the connecting part from the rear to the middle part didn't fit perfect but we thought it was because it was the 3d printed material used (this is the headache for later).


Once we had this, we were excited to start production! Things couldn't get better. We were ready to make the molds and get the product out!

The first set came! It was great! Plastics were made so well and the product was very durable! Much more durable than the OEM ones. It was perfect... upon first glance...

Then we fit them into our test NSX in Osaka; and well... this is where the problems came.

Problem one:
When I made the tabs, I forgot to make space for the rubber seal for the vent at the door part -- so back to the drawing board.

Problem two:
The connection piece still was too difficult to put together.

Problem three:
Because of the two above, the door was more difficult to open. Everything fit perfectly, but just more difficult to open.

Photos and videos:

What we thought was an easy project turned out to be a much more difficult task. Back to the drawing boards. We needed to first fix the tabs for the large door part. Which we did; thankfully now the seal can fit. But the biggest problem was the connection part. For this we needed to go back to the OEM part. We needed to change the whole mold to accommodate this! We tried 3 versions before but none seemed to fit perfectly. We needed to remake the whole mold based off the OEM part just to make sure it is correct. In fact, we needed to remake all 3 molds to make it like the OEM ones now.

Now we're here. The third final rendition.
Now the connection pieces fit. The seal fits in. Everything is looking good. We just need to fit it in the door now and make sure it still does not have the same issue as the beginning. BTW that issue was because the plastic was too thick and too durable; we needed to make it a tad less thick.

Let's hope this is the final time we need to test. But this will all be worth it for that perfect OEM replacement. Especially since these are much needed to replace the always breaking parts that Honda made back in the 90s. Also in case when they inevitably discontinue the door liners...


We'll be imprinting a leather texture like the OEM ones to make sure they are correct and look and perform better than the OEM ones.

To those who pre-ordered,
I know it's been delayed like crazy and this was not what I wanted. But I really hope you can see the investment in these and the time and effort we're spending to make sure you all receive a perfect product rather than a flawed product. We're taking a lot of time and effort to make sure these are the future for NSX parts and to help keep our NSXs on the roads.
Amazing that we have the ability and the backing of a company to do this work. Thanks to all your input and effort on your end and for MITA being involved with the NSX. I feel like I bought an older NSX at the right time because of things like this being offered.
Its nice to see independents stepping up to provide an alternate source of parts.
It's definitely a challenge to get these to be perfect. We finally found a great way to reinforce the brittle door liners. The final product will be made much more durable than the OEM ones and will always be available (especially when Honda decides to discontinue these).

We are going to start the leather print process now and try to get these out before the holidays! We will most likely be having a bundle sale for all of our reinforced parts as a "maintenance package" for the winter months.
Looks like we're finished with them! They're shipping/shipped to the pre-order customers already. RFY in Japan will start to carry these too.

I wish I can post photos but the new system won't let me. Photos and availability here:

We still have a ton of them. But they are running up.
Just got my new door liners from Mita. They fit perfect but several of the screw holes are way oversized. I had to use washers at several locations because the factory screw heads were the size of the holes. There’s also no thin foam tape to prevent squeaks like the factory pieces. Overall they are very good and I’m glad Mita is offering this to us.
Just received these as well and am looking forward to installing them. Does anybody have a source for the correct anti-squeak tape? I'm seeing a lot of variations in quality/price/type when I search for "anti-squeak" or flocking tape, and want to make sure I have the right stuff.