16 ms·
What we learned making a plastic injection mold with a Chinese mold maker
- giantrobot 3y ago[flagged]
- deleted 3y ago[deleted]
- sircastor 3y agoThey either don’t know they’re not complying or they hope no one will notice.
- grecy 3y agoReally interesting, thanks. Can you provide ball-park costs - how much was your mold, and how much did you pay for 5,000 units to be made? Even if just a rough estimate that would be really helpful, thanks.
- iancmceachern 3y agoI'm not the author but tools I've purchased in the past are usually $3-8k for most smaller parts and $15-25k for larger or more complex parts from a lower cost/overseas place and lower volume tools and much more from a US or European shop for a high volume steel tool. Parts are then a few bucks a part or less, depending on size and particular material.
- ahaucnx 3y agoAuthor here. Our mold costs were in the USD 5k - 10k range. Price per plastic part really depends on the weight and the material but you can probably assume USD 1 - 4 per part.
- LastTrain 3y agoThanks. Does that include all of the professional services talked about in the article?
- OldGuyInTheClub 3y agoBill Hammack, "The Engineer Guy" explains injection molding here: https://www.youtube.com/watch?v=RMjtmsr3CqA https://www.youtube.com/watch?v=RMjtmsr3CqA Interesting history of a process that's everywhere and invisible at the same time.
- irjustin 3y agoKeyboard.io's blog has in great detail, all the problems, wins with working with Chinese manufactuerers from wood workers, plastic injection, assembly, etc. Highly recommend it because they give a lot of details and if you start from the beginning you can really see how they learned how difficult it was in going into the space. The multiple visits, quality control, the issues with who owns what, and where they lost money. https://shop.keyboard.io/blogs/news?page=19 https://shop.keyboard.io/blogs/news?page=19
- hef19898 3y agoDoes one of their lessons-learned include to hire proper engineers and supply chain peoole with experience in China / with Chinese manufacturers? Ideally all the way up to, say, COO, and give those people tze necessary authority to run things? Because if not, it is just a collection of anecdotes of the clueless, a collection that is used for content marketing...
- roel_v 3y ago" it is just a collection of anecdotes of the clueless" But those are the entertaining ones innit. What fun is it to read a blog (like OP) that says 'yeah we hired a bunch of experienced professionals and we didn't have any problems'. No, we want to read stories of 'so I forgot about one detail and the manufacturer completely misunderstood us so I had to fly to China and spend 100k to get it fixed and it still was 3 months late'.
- TheSpiceIsLife 3y agoBy the time you do all that, effectively moved in to the Design By Committee Industry, what distinguishes your widget from ACME Big Widget Co & Sons. And employing all those people doesn't guarantee success, but it does guarantee your failures will cost a lot. You'd probably want to only attempt making something like this as a vanity project, where it matters less if you fail, and thereby half the fun is navigating the path to success by yoursel[f/ves].
- obrajesse 3y agoI mean, we're a two person company. I can assure you that all that writing wasn't about content marketing. But, just for completeness sake, the list of people who got blindsided by the con artist who was ultimately behind a lot of the crazy included both our experienced local on-the-ground project manager and the factory owner.
- userbinator 3y agoYou cannot have 90 degrees in your mold. For the mold to exit your plastic part, it needs to have a slight angle of a few degrees. This is known as "draft": https://en.wikipedia.org/wiki/Draft_(engineering) https://en.wikipedia.org/wiki/Draft_(engineering) I'm more familiar with metal casting, but plastic injection molding seems to have a lot of similarities, such as shrinkage and flow considerations.
- deleted 3y ago[deleted]
- justinator 3y agoThe way Lego bricks are injection molded is quite fascinating.
- jdblair 3y agoThis was famously an issue with the original NeXT Cube: Recounted in an article in Fast Company: As Isaacson relates in Steve Jobs, most parts cast in molds have an angle that is slightly greater than 90 degrees, because the extra degrees make it much easier to get the parts out of the mold. That’s the kind of compromise neither Esslinger or Jobs was willing to make for the NeXT, arguing it would ruin the “purity and perfection” of the NeXT cube. So the sides had to be produced separately, using molds that cost $650,000, at a specialty machine shop in Chicago. https://www.fastcompany.com/3056684/remembering-the-design-legacy-of-steve-jobss-other-great-computer-company https://www.fastcompany.com/3056684/remembering-the-design-l...:
- askiiart 3y agoIt's taking a really long time to load for me, is anyone else having this issue? HN hug of death maybe, now that it got upranked?
- aikinai 3y agoI was just setting up an AirGradient and was annoyed the site was slow as I was referencing some documentation. Then I come here and see why!
- lbourdages 3y agoMirror: https://archive.ph/TiNXf https://archive.ph/TiNXf
- XorNot 3y agoAnyone know if AirGradient plays nicely with Home Assistant? i.e. running local without the cloud? I've been in the market for a few more CO2/air quality monitors around the house, but I'm unhappy with the very proprietary nature of the uHoo and it's incredible expense.
- ftigis 3y agoThere's this bit in the description: https://www.airgradient.com/indoor/#:~:text=The%20AirGradient%20Open,assistant%20with%20ESPHome https://www.airgradient.com/indoor/#:~:text=The%20AirGradien....
- starky 3y agoYes, I've got my DIY one working with Home Assistant. It is just running on an ESP32 so you can load a configuration to it via ESPHome [1]. [1] https://github.com/ajfriesen/esphome-AirGradient https://github.com/ajfriesen/esphome-AirGradient
- montjoy 3y agoHA has made it really easy to flash the esp chip. You just plug the chip directly into your computer for the initial flash. After that you can do it remotely.
- ahaucnx 3y agoAchim from AirGradient here. Yes all our monitors [1] work nicely with Home Assistant. Especially via ESPHome [2]. [1] https://www.airgradient.com/indoor/ https://www.airgradient.com/indoor/ [2] https://www.airgradient.com/integrations/home-assistant-esp-home/ https://www.airgradient.com/integrations/home-assistant-esp-...
- robga 3y agoI run several self built Air Gradients on ESPHome and they do not connect to the cloud - or any external service. Works well with HA. Rock solid for 2+ years. I have to reboot them every 6-9mo or so if they “freeze”.
- 3y ago
- krisoft 3y agoSo, what is Chinese specific about any of this advice? Every single word of this would apply the same if the factory were Indian, German, or Canadian.
- xwolfi 3y agoThe experience of the writer. I'm not sure he meant anything special about us in China in his writing, he seems to be even satisfied working with us !
- mitthrowaway2 3y agoIn my experience, there is a substantial difference: the Canadian factory never replies to a quote request.
- sfmike 3y agoAgreed in China they'll respond to anything which is a Pro, in USA experience as well has been maybe they'll respond but the email will get a casual 1 line response in 2 weeks. There are certainly cultural differences between working with China versus other places and like anywhere else has pros and cons.
- mips_r4300i 3y agoChinese shops will always say yes to whatever question you ask. Can you do XYZ impossible feature? yes! Can you do it for cheap? Yes! Etc,etc The guy at the front of the business will BS you hard to get you in. Later their DFM guy will make subtle, or not subtle changes to your CAD files because they realized they have to actually make it. Or, they sub it out and take a cut off the top. I have seen designs completely reverse engineered and recreated wholesale from a step file to fix numerous unpredictable features. The client did not realize this until the tooling was already produced. The YOLO factor cannot be understated. It can both work for and against you.
- starky 3y agoAgreed, this is all just the basics on how an injection molding project goes. There is tons more involved in learning how to work specifically with Chinese manufacturers so you get the product that you require. Things like how building a relationship with your vendor being incredibly important to doing business with Chinese companies are not covered here.
- quasse 3y agoThis is the type of stuff that trips up many Kickstarter / crowd funded projects. "I have a great idea, I'll just manufacture it in China and sell it as a product!" This is a great overview of the process and complexity for *one part* of the manufacturing process for bringing a product to market and almost all of them are as complex (or more) and have pitfalls of their own. Add on wiring harness mfg, PCB/PCBA, machined parts, compliance testing, final assembly, QA testing, and revision management and then you're about halfway to running a successful product business. From personal experience, the best advice in the article is to hire a domain expert when moving into a field you aren't intimately familiar with. Employing them for as little as a few months can help you avoid several years of very expensive lessons as you figure a new process out.
- andy_ppp 3y agoI wonder why with things like this people don’t get that it involves real experience and expertise to get parts made correctly. Surely there are people offering their services to avoid these mistakes who have the relevant skills. Making things is much harder than software in some really important ways, are these computer programmers demonstrating hubris?
- wmf 3y agoPeople just assume that the factory already has that expertise included with their services.
- jpgvm 3y agoIt is available sometimes (at a price). There are some upsides, namely in-house experts are more familiar with that specific suppliers processes and capabilities. Downsides are obvious, they work for the supplier and not for you.
- exmadscientist 3y agoThe factory can help with a lot of this (if you incentivize them appropriately). The factory can never help tweak your initial concept, right at the beginning of development (when it's ~free!), to save tremendously on future production cost. That's what you hire the consultants for.* *Disclaimer: I'm just such a consultant, though I work on the EE side.
- ck2 3y agoHoping AirGradient can become a serious competitor to the far too expensive PurpleAir But they cannot compete with the purple network in the USA right now. I've suggested this before but if they somehow partnered with WeatherSTEM that could change things in a hurry. Even if they had to provide discounted units. WeatherSTEM appeared to have their own open database so I think the costs of long-term data storage would be avoided once integrated.
- Johnny555 3y ago>Hoping AirGradient can become a serious competitor to the far too expensive PurpleAir AirGradient's outdoor sensor costs $155, Purple's is $229, is 50% higher price "far too expensive"? From your comment, I expected Purple's to cost several times more.
- andrewstuart 3y agoOne day I looked around at all the plastics in life - in particular looking at the plastic cases of vintage computers, and I realised that plastics is absolutely incredible. Often really beautiful when you think about it, incredibly precise, with beautiful lines and curves. I've come to find plastics really quite interesting. It's kind of a magic material. And at the same time it's a sort of like King Midas in which humanity gets this incredible material but now there's plastic everywhere polluting everything. Everything we touch is turning to plastic.
- asdff 3y agoI had a different sort of event looking at the plastic in my life. More like, whats the point of this, other than to save the manufacturer costs? I'm convinced there's nothing I own thats made of plastic that my grandparents didn't have a much nicer all metal or wood version. Not to mention its unrepeatable and tends to get brittle with age. So much plastic stuff I have is straight up junk that's just going to fall apart in a few years. Meanwhile you can have a metal can opener thats 80 years old and works as good as new.
- yjftsjthsd-h 3y ago> More like, whats the point of this, other than to save the manufacturer costs? That also translates to customer cost
- nl 3y agoThis is generally an argument that has merit only if you can ignore cost and care completely. Yes, silk parachutes exist. But there was a reason why nylon was revolutionary - it was orders of magnitude cheaper and required a lot less care. > Not to mention its unrepeatable and tends to get brittle with age. Meanwhile you can have a metal can opener thats 80 years old and works as good as new. Plenty of metal can openers that are rusted, bent out of shape, or corroded enough to be unusable. Plastic only usually gets brittle if it is left in sunlight (and not always then). Not sure what "unrepeatable" means in this context, but plastic is usually at least as repairable as wood or metal by using resin. Indeed, both wood and metal is often repaired by using resin based fillers.
- geokon 3y agoOut of curiosity, wouldn't it be easier/cheaper/faster to use some existing off-the-shelf design and drill/machine some holes if you need it slightly modified? It seems everyone reinvents the plastic-rectangle-with-grooves. Is there some obvious reason for this? And is there some canonical place you can get some proven high-quality boxes in bulk? A friend and I made some sensor boards and used off the shelf waterproof enclosures - but I wonder if there is some go-to standard enclosures that people go for
- starky 3y agoMachining time is expensive, so at some point it makes a lot more sense to just pay for the tool that will produce the exact part you want for a fraction of the price. For low volume stuff Hammond Manufacturing makes a variety of plastic and aluminum boxes for electronics projects. No to mention, if you want a unique industrial design for your product to stand out then you are going to need custom tooling.
- bambax 3y agoAnother approach, for low volume and if the target user can do a little assembly, is to make something out of laser cut plaques of plywood or plexi. It's simple to make and easier to ship (because it's flat until it's assembled). The Ikea way, if you will. I do this for my personal projects (volume < 5) and the results are nice and functional. You can also cut holes for buttons and whatnot and you get something well tailored for your needs.
- devsda 3y agoIf it can be 3D printed, is (commercial?) 3D printing more affordable/efficient for such low volumes ?
- bambax 3y agoIn my experience it mostly depends on the size of the piece. Commercial 3D printing can produce beautiful and strong objects, but they are size limited and the price goes up fast with the size. Laser cutting can be quite big and make a large volume box, if that's what you need. And transparent plexi is nice (if it fits your needs).
- c_o_n_v_e_x 3y agoI didn't see it mentioned, but depending on the type of volumes you're working with, you can opt for a more durable, expensive steel mold vs a cheaper aluminum mold. The molds wear out over time, steel will typically last longer. For one of our products, we used an off the shelf plastic enclosure. Unfortunately, the process of getting our equipment certified with an off the shelf enclosure was much more difficult than expected. Finding an enclosure manufacturer who would support us through certification was challenging.. the sticking point was trying to get manufacturers to provide test samples of the gasket materials being used.
- xxs 3y agoThe box doesn't appear to have (glass) fiber reinforcement, so I guess the mold is Al. The article doesn't mentioned the type of plastic being used, either - by the looks of the video PP or ABS?
- ahaucnx 3y agoAuthor here. We use ASA plastic.
- unleaded 3y agoHow do you decide what plastic to use?
- ahaucnx 3y agoUV residence, hardness, mold suitability characteristics etc.
- xxs 3y ago(: ASA, the better ABS. I guess it's ok for a mounted enclosure. One thing that I consider a test for quality - cheap plastic enclosures/shells (esp. shells for tools). PC/PA6/PA66/PC+ABS/POM(!)/PP+GF/HDPE all good (esp. with fiber reinforcement for PC/PA). I can't recall the last time I have seen ASA, aside quick connect garden fittings. Out of curiosity: what else have you considered as material?
- Roark66 3y agoIts a nice article regardless if you're going to manufacture in China or anywhere else, but a crucial bit of information for China manufacturing is missing. What about IP theft? Does keeping your mold make it more difficult for people wanting to make knockoffs of your parts? Does moving it to a different plastic injection part maker help? Is there anything you can do, or is it essentially something you account for when "manufacturing in China" and you send them components you don't really care that much about?
- ahaucnx 3y agoAuthor here. Yes this is a good point but did not really apply to us as all our air quality monitors are open-hardware anyway.
- roel_v 3y agoJust out of curiosity, did you investigate how much more expensive it would be to have molds made somewhere in the West? Is that even available at all for relatively small and inexpensive molds/projects/orders like yours?
- h317 3y agoNot the topic poster, but speaking from the similar experience, the cost can be as low as $4,000 in China for the size of these parts. In USA/Canada it would start with a $60k minimum, and with a 6 month timeline instead of 1. And 9 times out of ten, the local fab is making their moulds in China anyway.
- mips_r4300i 3y agoThis is similar to my experiences, the really good ones still in the US have heavily specialized on high-end boutique orders. They can be very competent but also very non competitive for any normal work. Same with with US based PCB shops. They all want to do high dollar ITAR restricted boards for govt contractors. There is a middle ground. US sub shops that oversee captive Chinese operations with their own crew and keep you in the loop. This worked well for my personal projects and wasn't too horrendous. About 16k for a simple design that I could've had done with our work team for about 8k. But I never had to fly over, play WeChat tag in Mandarin, and I got PowerPoint DFM updates regularly.
- iancmceachern 3y agoA lot of these challenges can be avoided by hiring an experienced mechanical engineer, product designer, etc. Many of these things you would expect not to leave the initial design phase that way.
- washadjeffmad 3y agoJust thinking that. Granted our artists have access to a lot of resources, but their designs have been trialed in house and are functionally complete before engaging engineering. It's kind of cool that someone can basically walk up to manufacturing and still get it done, though. I never would have considered that.
- FpUser 3y agoOne of the reasons I've decided on using sheet metal for a part rather then plastic injection mold.
- tommiegannert 3y agoThanks for sharing! How did you find your mold maker and consultant? > It is super important that you review in depth this mold 3D with your own expert as sometimes mold makers try to do shortcuts that save them money but could create problems later on. Any examples?
- Kosirich 3y agoQuestions to the author whom I see is reading the comments: - What is the plastic used for the part (ABS, PC)? - What was the material for core/cavity (tool steel)? - What was the lowest tolerance on the part? - Were US/EU manufacturers considered at all?
- ahaucnx 3y ago- ASA - DIN 2738 tool steel - I don't know the tolerances. My engineer probably knows - Not considered
- deleted 3y ago[deleted]
- tzs 3y agoOnce you have molds, make sure you control them. Here's a story [1] of a company that found that the Taiwanese plastic company that made its custom parts stopped responding after 15 years. They got another one of their Taiwanese suppliers to go to the plastic company to see what was going on--and found that the factory was now a hotel and the sales office was a now a strip mall. [1] https://www.stlpr.org/arts/2013-07-24/on-chess-the-case-of-the-missing-molds https://www.stlpr.org/arts/2013-07-24/on-chess-the-case-of-t...
- sarchertech 3y agoIf you don’t have people on the ground how can you control them? Also if we’re talking about China and not Taiwan, even if you do have people on the ground, how likely are you to win any kind of contract dispute?
- thesaintlives 3y agoExcellent info! Thank you. Can I ask why it was not possible to find a USA mold maker? Even if you have to pay a little more surely it is better supporting jobs and prosperity at home? Thanks!
- londons_explore 3y agoIs it really worth making a mould for making 500-1000 units? At those kinds of quantities, I would just fire up the 3D printer, and leave it printing in the corner of the office for a few weeks (with an auto-ejector). It would end up costing ~10 cents/part, assuming you already have a 3d printer for prototyping and already have someone who knows how to load a new reel of filament into it every morning and evening. Thats hard to beat for anything under 10k units...
- Agree2468 3y agoThey provide .stl files for you to 3d print your own enclosure, or presumably order form a third party printer. I assume this shell is specifically for those who are concerned with appearance and/or fire resistance (PLA is pretty flammable.)
- deleted 3y ago[deleted]
- jbgreer 3y agoRead the article and found myself nodding along. If you work with larger Contract Manufacturers, they often have design for manufacturing centers that will perform mold analysis and suggest modifications. They often have the advantage of having worked on lots of different designs. And even further down the road: make sure to account downtime in your production schedule for mold maintenance. I see others commenting on registration, certification and approval matters and I’ll only say: do not underestimate the time and cost of that for a global product. This landscape changes all of the time. One minute a country will accept evidence of an FCC filing; the next minute they require in country testing with a local authority.
- versteegen 3y agoMy dad was (amongst many other things) a toolmaker who made plastic injection molds. These things can be hideously complicated, especially if the designer doesn't understand how it will actually be built, and as a result he once spent a year on one. In his days everything was manual, no CNC, no 3D models, no simulations, and probably no contact with the designer to make improvements. He had to cut milling bits with custom profiles to cut custom tools such as a series of graphite and copper spark eroder forms to cut just some of the corners and shapes in the (paper) technical drawings, then repeat for the next ill-advised bevel or interior sharp angle or even lettering which is too close together to get a milling bit inbetween two letters. Figuring that out was his responsibility alone. Instead of computer control, he'd have to do something like first create a scale model of part of the tool out of a block of plastic, then use a pantograph (a mechanical linkage allowing you to trace a shape with a pen and have the movement magnified/minified) to copy the shapes on a milling machine -- even shapes that seem simple. And then maybe throw away (actually, take home as a souvenir) a month or two's work if you cut slightly too deep -- these were high precision parts. Not because the plastic had to be so precise, but because the completed dies are made out of many steel parts that have to fit tightly together and slide past each other, as you can see in the article. Considering the ~two months quoted in the article for this mold, I'd think a lot of that complexity is still essential despite modern computerized machining. I'm sure a great deal of ingenuity and many steps are still needed.
- versteegen 3y agoAddendum: I asked my dad and he said what I overlooked is that it takes far less thought and skill to make a mold or other tool today not just because of CNC (to cut paths you can't by manually turning knobs), but because of the algorithms that plan out how to make it.
- freddealmeida 3y agoI have done something similar. I just learned not to work with the chinese.
- t-3 3y agoSomewhat surprising mold production would even be considered to be sent to China. Every place I've been either does their own on-site or has a local partner doing the machining. After all, these are not mass-produced parts, they're generally one-off with dimensions and fixtures designed to fit specific machines and materials.
- icegreentea2 3y agoHow do you iterate on the mold? I've worked at places that used local shops for both mold machining and the actual injection molding (we were in medical devices), so I never thought about that.
- t-3 3y agoRarely, touch-ups were done when necessary to molds in production (usually to fix damage caused by operator error, but sometimes to add new flash channels or fix other issues). AFAIK, iteration is usually kept to the prototype stage with aluminum molds and production molds are generally considered 'done'.
- bluerooibos 3y agoWhen I was a student I worked for a company who made injection moulded HDPE parts for fishing boat gear. After a few years on the market, the company noticed identical products coming out from China, the only difference being that the parts were far more brittle and broke easily (they still even had the company website printed into the plastic).
- jprete 3y agoI appreciate the point about not being 90 degrees because I periodically need plastic bins for board game organization and the ideal shape is a perfect rectangle of an even fraction of both box inner dimensions. At least now I know why all the kits for this use laser-cut balsa wood or foamboard with home assembly….
- proee 3y agoWhat are some typical costs for getting such a mold made, and what are the per unit costs of the enclosure once it goes into production?
- EvanAnderson 3y agoThere's a middle ground to creating a dedicated mold in MUD tooling[0]. Your mold is a set of inserts that go into a standardized base mold. You get less longevity out of a MUD mold, but it's typically much cheaper up front and you can reuse a substantial amount of the cavity and insert design when you go to a dedicated mold. I did work for a US contract moldmaker. The amount of knowledge about the performance of thermoplastics and metals was really impressive. They used some interesting off-the-shelf software to do simulations of mold performance, too. It was a fun gig. I appreciated the tactile, tangible technology that went into their operation. [0] https://www.dme.net/mud/ https://www.dme.net/mud/
- the__alchemist 3y agoIt's interesting how for electronics projects, injection-molded enclosures can dominate non-R&D/salary costs unless scale is very large. Ie, the PCB, electronic components, SMT assembly are probably not that expensive, especially with some of the ops out of Shenzhen available. Shipping materials, shipping costs to you and the customer add cost. Unintentional radiator certification adds cost. Intentional radiator certification adds more. All these together might cost 10% of the injection mold. One escape hatch is custom machined and printed ABS or metal enclosures, like from Polycase and Hammond. It is limiting and forces you to design around the enclosure, but is much cheaper for small/medium runs than injection molding. Ie a few hundred $USD upfront depending on turnaround time, enclosure size and material etc, then not much more than the plain enclosure per-unit. If you are injection-molding, hopefully you can use a 3D printer to prototype, but you may still end up screwing up the first (or more) mold due to issues highlighted in this article.
- twic 3y agoI bought a cheap little air quality meter recently. It has a power socket and battery compartment on the back. The manual says "DO NOT PUT BATTERIES IN THE BATTERY COMPARTMENT, THEY WILL NOT WORK". I would guess they reused the case from a previous product that supported battery power, in order to save tooling costs.
- deleted 3y ago[deleted]
- LastTrain 3y agoThat was an interesting read but sure would have been nice to have a cost breakdown, especially since the article made several references to cost tradeoffs. How can I understand the tradeoff of not hiring a consultant without having at least a ballpark idea of the costs involved?
- 93po 3y agoI bought one of their kits, spent a decent amount assembling it, and then 5+ hours trying to diagnose it only connecting to their dashboard once every few hours, and sometimes not for days at at time. Even a replacement ESP didn't fix it. Disappointed that it's not really functional for my needs given the cost.
- ahaucnx 3y agoPlease reach out (again) to me [1]. We are just launching a new main board with the ESP32-C3 that might fix your issue. Happy to send it you. [1] https://www.airgradient.com/support/ https://www.airgradient.com/support/
- 93po 3y agoThanks, I appreciate that. You/your team were also really responsive with the first ESP replacement.
- dieselgate 3y agoCool article, the piece that stuck out most to me is the "mold contract" bits about who owns the mold. Makes me think about early production FRP sailboats and stories about Company B purchasing hull mold from Company A when they're starting out.
- bsder 3y agoThey made a custom mold? At their volumes? Are they insane? They could have powder 3D printed this stuff for a very long time given the NRE on that complex of a mold. If they needed to control costs, they could have negotiated with a case supplier: https://www.takachi-enclosure.com/ https://www.takachi-enclosure.com/ Only after they were shipping enough product to make it worthwhile (100K+ units), should they even think about making a mold.