If manufacturers go silent after they see your design, it's not because they're busy. It's because your design just made their job more difficult than it needs to be. Nobody is going to tell you this upfront. If you're trying to bring a physical product to market, there's kind of this weird thing that happens. Manufacturers don't argue with you. They don't yell. They don't tell you it's a bad design. They just increase the quote, add to the lead times, and quit responding quickly. That silence is saying a lot. The response you want to get is, "Oh yeah, no problem. We do that all the time." In this video, I'm breaking down the designs the manufacturers silently hate. The ones that raise costs, slow production, and quietly put your job on the bottom of the priority list. This is a new channel for me, so if you like what I'm covering, please hit the subscribe button. Manufacturing is competitive, so everyone's going to tell you, "Yeah, we can do it." This could be that the salesperson is just completely out of touch, or maybe the shop really needs to work. Even if they currently have a 6 week backlog, they would rather have more lined up so that their machines never go idle. and they tell you they can make it, this might actually mean we can make it, but it's risky, slow, annoying, and we're going to charge you accordingly. If you can, get them on the phone. If they sound excited and carefree, that's a good sign. If they sound hesitant, ask them if there's an aspect of your design that is difficult and how you can work with them to make it less difficult for them. Even if the manufacturer seems excited about the product, still ask them because they might just be excited because they know they can charge a lot. Manufacturers aren't paid to educate you. When you supply a design to a manufacturer, they assume you've worked everything out. A manufacturer will never tell you there's a problem with your design. If anything, they'll get back with you and tell you that they're having a problem making it for some reason or another. They get paid to ship parts, not to redesign them. That being said, you will deal with some suppliers that have in-house engineering. They'll work with you and they'll help you overcome manufacturing issues. However, keep in mind this is not a design consulting service. The changes they recommend are to make it easier for them to make the part. Sometimes the change they want can be detrimental to your design. So, don't just blindly accept what they're offering. However, sometimes they know something that you don't. So, listen to them because sometimes they can save you a lot of money and a lot of problems. Don't be afraid to ask if they know a better process to make your part. If they have the ability in house, they'll probably jump on it right away. If this requires sending the part to a competitor, they're going to be a little more hesitant. But often times, if they know it's just not a part that's ideal for them, they will let you know. For example, if you have a really complicated part, but that part is very conducive to being an extrusion, they may tell you to get the extrusion made and then they'll just add the finishing features as opposed to machining out of an entire block of aluminum or steel. Ideally, you will have these engineering skills ahead of time or you'll be working with an engineer who knows how to modify your product so that it will be production ready. The point is focus on your strength. And if your strength is not the design of this product, then you need to get the people who can fill in your gaps and understanding. If you give the manufacturer something difficult, they'll rarely argue with you because they want the work. But that lack of arguing is going to show up in the invoice. If you want lower cost and better partners, you have to understand what they see when they open up the file you send them. Let's talk about designing a product without picking a manufacturing process. This is one of the fastest way to lose goodwill with your manufacturer. Many people will send a design of a part to a manufacturer with no manufacturing process in mind. You haven't decided, is this an injection molded part? Is it a CNC part? Is it a diecast part? Is it an extrusion? If you didn't take the manufacturing into account when you started, you're going to end up with a part that is poorly designed for every process. Manufacturers hate this because you're forcing them to reverse engineer your intent, not just the part, guessing on what the tolerances of the part need to be made. They're guessing on the surface finish, and they're guessing what matters and what doesn't. often times they won't know how that part interacts with other parts that it will be working with. And unless you give them a detailed explanation, chances are they're not even going to know what the part's for. When I send out a part, I never tell the manufacturer what it's for. I just tell them the information they need. This is the size. This is the shape. This is where the holes need to be. This is what the material finish needs to be. This is what it needs to be made from. That is not their job to help you design your product. There's so many aspects of your part that they don't know. They didn't design your product. They don't know the intent. They are not behind it. they are not pushing for. They just want to make you a good part that meets your spec that you are happy with and you pay your bill. Guessing equals risk and risk is expensive. Even with this higher pricing, you'll probably end up with an inferior product. Sometimes you'll get lucky and the part will come back and will do everything you need and it's great, but luck does not lead to success. Your design always needs to start with how is this made, not how should it look. If you really want to eat up a budget for no reason, specify tight tolerances on all parts. When I design a part, I make the tolerances as loose as they can be in order to get the quality product that I need. In some cases, a feature might be non-important, in which we can just call it a nominal dimension. If you have a feature that's 2 in, and you don't care if it's a/4 in bigger or 1/4 in smaller than that, then call out the tolerance. Marking this tolerance as such may allow the supplier to use an off-the-shelf material and not have to modify it for your purpose. If you need moderate tolerances, call it out. If you need tight tolerances somewhere, call it out and be specific. Don't ever make your entire drawing listing the same tight tolerances. I will be going over several videos in the future explaining how to call out tolerances. It's a pretty big subject, but a very important one. So, why do people call out tight tolerances in a design? Well, at some point along the line, people got this idea that if you have tight tolerances, you must be making a quality product. Manufacturers love to brag how tight of tolerances they can hold. In some ways, manufacturers are shooting themselves in the foot because they're encouraging the designer to build for high tolerances. Then a manufacturer gets a drawing with tight tolerances and now they're hating it. These tight tolerances slow down the machine. They make more scrap and they increase the inspection time. Most features don't need tight tolerances. When everything is critical, nothing is. You want the manufacturer to focus on the details that really matter. Don't overwhelm them. Good designs are selective. Bad designs are expensive and lazy. It's easy to just mark high tolerances across the entire design because then you know you're good. You could be double or tripling the cost of your part just because you're being lazy in the design process. One basic example that's often overlooked in the design process is putting sharp corners on internal features of a part. It looks clean in a CAD model, but it's a nightmare in real life. For machine work, tools can't make perfectly sharp corners. And if you try to just make it a really small corner, you're using really small tools and they cut very slow and they break. In molding, sharp corners cause stress and they cause the cracks and breaking. Manufacturers see sharp corners and they think tool wear rework and failures. Take the time to add fillets to your design. Fillets are a nice rounded edge that you put on parts. Not only do they make parts easier to produce, they can also look nice on the finished product. Internal fillets can significantly reduce the cost of making a part, especially for injection moldings. External fillets can sometimes increase the cost of the part a little bit, but they can add to a nice finished look. Just make sure you use standard fillet sizes so that the manufacturer can use standard size endmills to make your part or mold. Don't over complicate a part for no reason. You're not trying to win an art contest, especially if the part's not going to be seen. This can include organic shapes or complex curves. For these simple functional parts, keep them simple with squared corners and no additional features. Don't put tight tolerances on a surface that doesn't serve a function. Keep your aesthetic designs to only places where it truly matters. Manufacturers hate excessive complexities. This increases cycle time, requires special tooling, and increases the number of failed products that are going to be made. Every surface on a part should have a reason. If that reason is that it looks cool, be ready to pay for that option and make sure it's worth it. If you're making injection molded parts, make sure you don't ignore draft angles. Draft angles are slight deliberate angles put on the vertical surfaces of a part around 1 to 3° in order to make the part easier to remove from the mold. These are necessary for injection molding, casting, and thermal form parts. These also prevent scratching when the part comes out of the mold and reduce warping. Many designers forget to add these features. Generally, if you can design a 3-in draft angle into a part, you're pretty good across the board. For precision parts, you may be able to go down to half a degree, but you're going to pay for this. Improper draft angles leads to parts sticking in the mold, ejector marks, or damaged tooling. If you submit a part to a manufacturer without a draft angle on it, they're going to know that you don't know what you're doing. They're either going to insist that you modify your design or try to make it as is, and it's going to be very expensive. This is such a basic step. The last thing you want to do is look really dumb to your supplier. Because if you show up not knowing what you're doing, they're not going to want to take your work as much as someone who does know what they're doing because you're going to look like someone who has to have their handheld and is going to need a lot more time and expertise in order to get your simple product up and running. Another feature that they really hate is undercuts. And sometimes you do this on accident. Sometimes undercuts are needed, but you need to avoid them whenever possible. These are features where you have to come in with a tool and cut underneath something as opposed to cutting straight down. Machining this is very timeconuming and may require special tooling. In injection molded parts, you not only have this complicated tooling, but you end up with an injection molded part that won't come out of the mold unless you make special slides and releases or complex multi-art molds. Sometimes these are just a small lip or a recess fastener or hidden feature. Often times it's easy to just fix this in the design stage and never even have to deal with it in manufacturing. Once again, making unnecessary undercuts is going to make it look like you don't know what you're doing. I put together a free cheat sheet to help you go from ideiation through the production process and not skip any steps. I have it free for download down in the description and it'll help you out whether you're just getting started or you're advanced engineer and just want to make sure you don't skip any processes. Just click the link and I'll get it right over to you for free. Another killer is trying to make every surface on something look cosmetic. Not every surface needs to be perfect. And in fact, many of the surfaces, or maybe most of them, will never even be seen by the end user. However, many people like to treat every part as if it's a showpiece. If you've ever disassembled a car, you'll realize the further you dig into a car, the rougher the parts start looking. This is not a design flaw. It's just unnecessary because you were never meant to see it. For hidden parts, you can usually just use a raw machining or maybe even a casting that still has some flashing on it. When I have aluminum parts made, I usually just have them sand blasted and anodized. It's a fairly simple process. It's uniform, and they do it all day long, so it's not that expensive. So, if you need special surface finishes, that's great, but be very intentional and be ready to pay for it. When making injection molded parts, having a surface that's textured or highly polished is expensive. So, make sure you call that out and just the feature that requires it. So, now it's time to talk about the assembly strategy. At some point, all these parts you've designed and manufactured have to come together. This might be done by you, it might be done by the manufacturer, or it might go to a third party. You should know how all these parts go together, in what order, and how they will be held in a fixture for assembly. You need to know the torque specification of every fastener and also know anything special such as a surface that must be cleaned before it's glued or painted. Don't wait until all the parts are made to figure this out. You should be 90% of the way there before you even go to manufacturing. I will be doing detailed videos in the future on design for assembly and design for manufacturing. So, make sure you stick around for those. You need to know exactly what tools and fixtures will need to be used to put your product together, and those should be ready when your manufactured parts get there. The design of the assembly fixtures should be tied in with the design of the product itself. I typically design and machine or weld my own fixtures. However, if I wasn't going to, I would have the company that makes my prototype parts also make the fixtures. Making proper fixtures is very important. Your fixture needs to have proper alignment features so a part can't be put on wrong. Don't ever rely on the assembler to properly align a part. The fixture should hold the part in the way that is easiest and quickest for the assembler to put it together and the least likely for them to make a mistake. Standardize parts wherever you can. This leads to a reduction in air, speeds up assembly, and reduces the number of tools necessary to assemble your product. It's always fun to customize your product, but manufacturers love repeatability. Every unique part means separate tooling, separate inventory, and separate quality checks. Add just one small option to a finished product, and you can double the amount of inventory you have to carry. Make two small options on every given product, and you now have four times as much inventory you have to carry. Make sure these options are necessary. Often times giving a customer too many options will actually reduce your sale because you're asking them to go through the trouble of figuring out the differences and which one they need. If two parts can be made the same, do it. If you have a right-hand part and a left-hand part, and you can put the right hand and the left-h hand features on the same part, you can cut the amount of parts you need in half because you can use that part in both places. This can cut your tooling in half. This can cut your inventory in half. And it's going to make your assembly line cleaner and easier to use because there's fewer parts to grab. The customer doesn't see the standardization, but your pocketbook will. Don't use exotic materials for no reason. Some things sound really impressive. This product is made of Kevlar, build aluminum, nanotechnology. The list goes on. In addition to high material cost, special materials can lead to long lead times, hard to procure, or require special handling. If you need the wow factor, great, but only use it where you need it. Use exotic materials in strategic ways. Use them where you're going to get the real bang for the buck out of them. Manufacturers prefer to use materials they know. When you add something special, this adds an entire supply chain logistic that they are not used to dealing with. Risk equals cost and they know it. Manufacturers love predictable processes. They hate parts that require hand trimming, manual bending, or just tweak its steps. Sometimes this is unavoidable. Even today, in advanced automotive manufacturing lines, they still have a guy who hand tweaks the door to make sure it closes right. They used to do this by adding some shims and putting a 2x4 in the door and slamming it in just the right way until it aligned. That was 100 years ago. So now they basically have a little piece of metal that they bend it, which is essentially the same thing that they were doing 100 years ago. Sometimes this manual work is unavoidable, but it does lead to inconsistencies. So do it only if you have to. These type of steps are going to require the most skilled and the highest paid worker on your entire assembly line. If the part can't be automated or easily assembled, the manufacturer is going to pad the quote accordingly. They're not being greedy. They're just being realistic. This isn't just for beginners. Advanced engineers can fall into the trap of designing for performance, elegance, or looking at theory over reality. Manufacturers are not impressed by cleverness. They're impressed by simplicity and repeatability. This gets us to the big problem that no one says out loud. Manufacturers hate designs that ignore them. This isn't an emotional special snowflake situation. It's just reality. These are designs that don't respect process limits, human limits, and cost limits. These are designs that will fight the production process every step of the way. But here's the turning point. that most founders miss. When you take on a manufacturer, they are your partner. Make yourself as easy to work with as possible. Be that customer that they pick up the phone for every time you call. Don't waste their time with things that you should have figured out before you went to them. Once you've gone as far as you can, ask them for their input. And I'm not talking about input on your design. I'm talking about input on what you can do to make it easier for them to make the part for you. Manufacturers love when you give them something that is simple, clear, and repeatable. They love when the tolerances are intentional, the materials are standard, and the assembly is easy. those designs feel safe. They know they can do the job and it'll pay their bills and they can move on. The last thing a supplier wants is to look at a design, know it's going to be problematic, know it's not going to come out right, and then have to deal with the backlash. No one likes a problem customer. But here's the one thing that changes everything. Before you finalize any design, ask yourself, if I had to make 10,000 of these myself, would I be hating life? That question exposes over complexity, fragility, and wishful thinking. If your answer is yes, what do you think the manufacturer is going to feel? If you want honesty from your supplier, earn it by being better. Avoid being that guy. That doesn't mean you have to be perfect. It just means you need to be aware. You need to be willing to listen, and you need to be willing to work with them to try to simplify the product and process. Manufacturers respond to effort, and they will do what they can to help you along the way. Here are some things to consider before you send your files out for quote. designs that respect manufacturers get rewarded with lower cost, quicker turnaround times, better relationships, and an overall better experience. Those advantages compound pretty quickly when you're trying to run a business.
