Production Update - Production Samples Reviewed
over 3 years ago
– Wed, Aug 26, 2020 at 05:53:32 PM
Grab a coffee or a cold one, and sit back in a comfy chair or hammock, because this is going to be a long and detail-rich update!
The production samples arrived! There were some delays with the samples due to broken drill bits. A broken drill bit holding up production? That may seem trivial, but the drill bits used to remove the material from inside the marker body are specialty bits that you don't just have on hand. They are a specific diameter, carbide, extra-long with thru-coolant holes for keeping the titanium as cool as possible during the deep hole drill. Some of these bits cost over $500 and have replaceable inserts. Not something you want to break on a regular basis. Once the machining parameters are tuned in for production, things go much smoother.
Yes, that is a black titanium Marksmith next to the natural Ti Marksmith. It's beautiful. Unfortunately, I'm not going to make these yet, because I need to do some long term durability testing of the black coating.
I had the samples made in 3 different finishes to compare them. The brushed finish like what was shown in the Kickstarter. A bead blasted finish, which is more matte, but unfortunately scratches too easily and can't be refinished by hand with a scotch-brite pad like the brushed finish. And a black finish which is supposed to be the most durable black finish available for Ti.
Did the Production Samples Pass the Test?
Yes and No. The samples were good, but a few things have to be tweaked and we're gonna need another sample run before production.
The exterior machining of the clip is perfect, exactly like I wanted it. I am thoroughly impressed by every single machining detail of the clip because it is the most geometry complex part of the Marksmith.
The screws were changed from flatheads to low profile Torx socket cap screws. This change makes the height of the screw in the counterbored hole more consistent so that the screws are always flush with the surface. Flathead screws are much more difficult to always make flush with the surface, especially since small dimensional changes in the screw head between batches can cause the screws to be too high or too low, even if the machining of the part they fit into is consistent. I experience that with my kitchen knife handle making, where the flathead black, silver, and gold screws that I purchase all have slightly different head diameters, which cause the screws to be at different heights even though we CNC machine the countersinks.
The external dimensions and most internal dimensions are perfect.
The brushed surface finish looks amazing and is easy to keep looking like that.
An o-ring was added to the screw connection between the tip and the body. This keeps the tip on tight and prevents it from loosening.
The Things that Need to be Fixed Before Production
1. The main issue was that the internal features were about 1mm too short to properly extend the cartridge. Let me step back a minute and explain how this happened. The prototypes were made by us in our shop, so we made everything to spec. My shop equipment is oriented towards prototyping, so it would not be efficient for us to produce these. However, the end goal is to invest in production CNC equipment to be able to make future products like this. During the design and prototyping phase, I worked closely with the machine shop that is making these for us to make sure that the design would be producible. It's too easy to design and prototype something that is very difficult to manufacture, so it's best to communicate with those who will be making the parts during the design phase. I shared CAD models, drawings, and pictures with them on a regular basis for feedback. The only thing that I never provided them with was a real cartridge. Now the reason for this was to protect IP and to see how good they are at machining to drawing specifications and tolerances (a test of sorts). Specifically, I did not want them to make random adjustments to dimensions just to make the cartridge fit properly. If I was judging them only by the final functionality of the machined marker, they would have failed the test. However, after checking all the critical dimensions, they passed by about 85%. Most of their dimensions perfectly matched the drawing dimensions. However, there are 5 critical dimensions that form a tolerance loop which affects the travel of the cartridge during extension. 3 of those critical dimensions were out of tolerance. They were off by +0.34mm, +0.82, and -0.20, which added up to a tolerance loop stackup of 0.96mm, which was just enough for the extension to not function properly. I mean, this was right at the edge of working. If I pushed (too hard) it would lock into the extended position, but that is not acceptable. The issues here were probably because non of these dimensions are directly measurable using calipers. 2 or more dimensions have to be measured to calculate the dimension. The QC department will have to pay close attention to these dimensions in production.
Now that I am confident in the quality of their work, I have sent them the cartridges to be used by them to check the functionality of each Marksmith body. Would it have compressed the production schedule if they had the cartridges in hand while making the samples? Probably, but they could have also used them to fudge the dimensions around to fit instead of machining from the design dimensions.
2. The width of the clip neck that passes through the body to the slider inside was changed, but the slot width was not, leaving a slot that was a bit too tight. They widened the clip neck by 0.5mm from my design to increase the strength, because the screw holes are close to the wall, but they forgot to widen the slot by the same amount.
3. The clip mounting to the slide was off-center. This is an F up that can't be justified, especially considering the high quality of the rest of their work. The screw holes were not centered, and all of the samples were like this. Someone set up the zero wrong when machining the screw holes.
4. Burrs inside the slide were grabbing the tail of the cartridge. Some samples had it, some were clean. Those must always be free of burrs.
5. A radius was missing that creates a smooth transition for pushing the clip to the side to retract the cartridge. This made it more difficult to retract the clip. I prefer the smooth ramped motion as I designed it. After close inspection, what I think happened is that they messed up the machining there, and then hand filed it to match the drawing dimensions. These are pre-production samples, and as such its normal for things to get hand-filed sometimes. Anyways, they know this needs to be done right.
All these points have been discussed with the machine shop, and they are working on new samples incorporating these changes. They said it's going to take then about 15-20 days, but from experience with any manufacture, it's likely that there will be some delays.
As many backers have pointed out, September is around the corner. It's going to take about 15-20 days (starting from August 19th) to complete the new samples, a few more days to ship, a few more days to analyze, document, and hopefully confirm the first production run. So that means production will begin in the second to the third week of September, and the first production run will take about 3-4 weeks. The first Marksmiths could ship in mid-October.
Why is this taking longer than the Estimated Delivery?
It's easy to blame COVID for everything these days, but it really has had repercussions everywhere that I did not consider when the project was launched. This project was launched on the second day of the first week of the stay at home orders that took effect in GA and most of the US. Things felt smooth for the first few weeks, and the govt thought all might be in the clear after that. Well, the fact that kids (including ours) have not gone back to school yet and are doing virtual learning means that the time I have to work at the office/shop has been cut in half because my wife also continues to work and we have to bounce back and forth between taking care of kids. This affects the business and factories that I work with also because they are now understaffed and less efficient since some of their employees have to stay home with kids that would normally be at school. The rest of Engineerable's team does not have children, so they are continuing to mostly work normal hours and can take care of the making and shipping stuff, but I'm the one that does new product development.
I should have engaged the machine shop to make the samples during the time that the Kickstarter campaign was running. Instead, I continued to make improvements, testing and tweaking the design to perfection, such that they only began the samples after the campaign had ended. It extended the production time, but the result will be the best marker.
The machine shop took about twice as long (2 months instead of 3-4 weeks quoted) due to delays like a broken drill bit and getting the finishes right. It was a mistake to ask them to do different finishes. I thought it would save time to machine them all at once, and then I specifically asked them to ship the brushed finish first, and not let the other finishes delay the shipment of the brushed finish. Well, the way they did it, they had to wait until all of them were complete before shipping. Lesson learned, just ask for what I need, and do other versions later.
What happened when the samples arrived? Members of my family got COVID! Fortunately, it was mild and everyone is ok, but that has put me out of the shop for almost a month due to quarantine. I know quarantine is only supposed to be 14 days, but that's for a single person. When different people in a household catch it at different times, that extends the quarantine. So, I was unable to review the samples right away. I had to review remotely with my shop machinist, and he caught most of the issues, but it wasn't until I was finally able to get my hands on them to take measurements that we were able to get down to the root cause of why they were not fully extending. It took about a week for me to review and write a very detailed engineering report documenting everything. From experience, I've learned that it's essential that every component or product has a manufacturing document and not to rely on the factory to keep track of changes. These even applies to ISO9001 and equivalently QC certified companies who are supposed to have all their ducks in a row. In the past, I have had parts made where I've spent a lot of time fixing issues (including packaging for shipping), and then I don't order them for a while, but the next time I order them it's like they have forgotten everything and we fall back to the beginning. Therefore I keep a manufacturing document of everything that gets made and send the updated version every time I place a new order.
Daniel and Team Engineerable