At what point does it make sense to 3D print a part compared to opting for injection molding? The short answer is “it depends.” The medium-sized answer is, “it depends on some back-of-the-envelope calculations specific to your project.” That is what [Slant 3D} proposes in a recent video that you can view below. The executive summary is that injection molding is great for when you want to churn out lots of the same parts, but you have to amortize the mold(s), cover shipping and storage, and find a way to deal with unsold inventory. In a hypothetical scenario in the video, a simple plastic widget may appear to cost just 10 cents vs 70 cents for the 3D printed part, but with all intermediate steps added in, the injection molded widget is suddenly over twice as expensive.
In the even longer answer to the question, you would have to account for the flexibility of the 3D printing pipeline, as it can be used on-demand and in print farms across the globe, which opens up the possibility of reducing shipping and storage costs to almost nothing. On the other hand, once you have enough demand for an item (e.g., millions of copies), it becomes potentially significantly cheaper than 3D printing again. Ultimately, it really depends on what the customer’s needs are, what kind of volumes they are looking at, the type of product, and a thousand other questions.
For low-volume prototyping and production, 3D printing is generally the winner, but at what point in ramping up production does switching to an injection molded plastic part start making sense? This does obviously not even account for the physical differences between IM and FDM (or SLA) printed parts, which may also have repercussions when switching. Clearly, this is not a question you want to flunk when it concerns a business that you are running. And of course, you should bear in mind that these numbers are put forth by a 3D printing company, so at the scale where molding becomes a reasonabe option, you’ll also want to do your own research.
While people make entire careers out of injection molding, you can do it yourself in small batches. You can even use your 3D printer in the process. If you try injection molding on your own, or with a professional service, be sure to do your homework and learn what you can to avoid making costly mistakes.
This video feels like an ad
All his videos feel like that. And he often makes assumptions suggestions about the stuff he’s talking about that aren’t grounded in reality. Watch his video on custom fan vents… It’s a riot of ill advised designs and bad ideas.
About 20 years ago I was involved with creating the design for and injection molded part. For a single cavity steel mold with a two moveable parts the tool cost $25K
(Note to moderators: I accidentally clicked on the ‘report’ button instead of ‘reply’. Oops, sorry.)
The cost of the injection moulding tool (‘mold’ in the text) can also vary dependent on making a hard or a soft unit. The soft tool might be good enough for several thousand plastics, when a hard tool will be good for tens of thousands.
Also: soft tools can be modified to make a small change relatively easily, whereas a hard tool may need to be completely redesigned.
I actually have a patent-pending new fast inexpensive way to make metal parts.
You can even just look at the “3d printed watertight bottle” where he literally brings in a none 3d printed plastic bag and puts it in the print
Absolutely agree with you! 100%. Some useful information in there from a practical point of view and some tips for 3d printing can be taken from it but some of the info is not true. I stopped watching their videos because of that, I found I was getting annoyed at the statements being made as if they were fact or there to help other people with print farms but I think it’s just marketing promo stuff for the most part.
He owns 3D printing farm. And he has plenty of great videos, i’ve learned so many things about how to make my 3d print designs MUCH better, i can fully reccomend anything he has on this topic. But he’s talking lots of crap about how bad traditional manufacturing methods are compared to 3d printing, which is wishful thinking and you might wanna take that with huge crystal of salt. Other than that the videos are super useful. And honestly there is something cool about his system which allows you to sell 3d prints of your design just by uploading/listing STL online, while his company does all the work…
I love 3D printing just as much as the next guy. The difference is the quality on an injection molded item will be far more superior. Injection molding isn’t subject to layer splits or breaking as easy. I’m all ok with a mix of 3D printed parts and injection molded parts for my final product. So far it’s 3D printed all the way and I wish I had a cnc machine to make my molds and an injection.
$1000 mold?! HAHAHAHAHA
This 👆
But on the flipside $1000 shipping vs $300 for supposedly identical-but-3D-printed parts?
The Slant guys do some decent videos on 3D printing but as comments above say, they also do a lot of very wishful thinking advertorials where they pull this stuff out of their backsides to sell their 3D printing services.
I think he’s saying shipping usa to usa is $300, while shipping china to usa is $1000. The same sized part, but different shipping. I think this is fair, because there are print farms all over the country – you can probably just drive over and pick up your parts if needed.
Lowest I’ve seen is 2k for a mold that is “temporary”, like only lasts a few 1000 parts, still, at that time, a lot cheaper then the manual labor of printing and checking a 1000 3D prints.
Oh, you noticed the lack of labor costs in the comparison chart?
For a small desktop injection molder like the busterbeagle3d?
Yeah, I know I’ve made 6061 molds for people and charged a bit less than 1k with shipping.
I had a realistic product a few years ago, all prototyped with 3d printing, but in the market I wanted to sell in buyers did r want 3d printed parts because it looked cheap. It required 3 injection molded parts (routed aluminium molds as far as I can recall), 1250 for the thinnest one and 1350 for the others. All about the width of an 8″ tablet screen but cents for each part. I had a couple of buyers already but it would never have paid off. I tried sanding, priming and painting and the time spent per item was insane. At that I abandoned the product. It was just too hefty a price point to even get a few off the ground. If I had 20 lined up to sell I think I would revisit it but it’s a huge start up cost.
I can certainly understand the video’s intent to keep various details simple with associated costs comparisons, but overall it tends to present a misleading narrative. For example, shipping cost from China to Canada…which tends to be more than China to US… is much cheaper than presented. I shipped two 4’x4’x’4′ pallets weighing 1000 lbs each from China (included all efforts/costs from collection to the freight forwarder) to Western Canada (so not just the Port) for $200 CAN landed in my City (600 miles away from the nearest port). Given the larger volume of shipping between China and the US, I suspect the price would be less… worst case … the same.
Also, there is no mention/comparison of the final quality between the injected part and the 3D printed part. Injection molding typically has higher quality results with much less after process refinishing. What about the part strength? 3D parts can be weaker depending upon the material used… so stronger material means the 3D print cost will be higher than other materials. What about the potential need for flammability rating? Indeed, 3D material can be found that is UL-94V rated, but it also costs more than “regular” material… which also increases the 3D printed cost. The there is the actual production time… I can have 5000+ injection parts made in a single day… how long would it take to 3D print 5000 parts even with 3D print farms.
That being said, I am not saying that 3D printing should not be considered, but that it is not nearly as simplistic as presented within the video. On my side, I use both technologies, but hands down I much prefer injection molding result.
That’s cheap. US$200 for 2 m^3 LCL would still be a good price. What forwarder did you use?
The shipping was handled by the Injection molding firm and so I just paid what they quoted. That said, I typically let the Overseas manufacturer/supplier handle all of the shipping, etc… as it tends to be much less hassle for me, but also they seem to get far better pricing than I ever could.
This video is really inaccurate. A box of 1000 reasonably sized parts will certainly cost less than $50 to ship internationally. Molds are generally extremely expensive. 1000$ is a disingenuously low estimate. Most of the time its 5-20k. Storage is basically free, even for a small company. Again 1000 of most parts will fit in a cardboard box which you can tuck away somewhere. Lastly, this doesn’t include the labor time inherent in using 3D printing. Or the engineering time for an injection mold.
TLDR; it’s more complicated than 4 line items.
Piece price should be much lower, basically cost of material plus overhead. Or much cheaper compared with 3D print.
I smell MBA.
Does anybody else smell MBA?
(Goes to find pitchfork and torch.)
Mr. HaHa, torches don’t quite align with our company’s climate goals. I’ve gone ahead and scheduled a meeting with HR for you to receive a refresher on company guidelines regarding team members’ individual carbon output. As far as the pitchfork I have looped in my counterpart in our AG dept. they will be in touch with you to discuss separately.
Regards,
MBA
Or an engineer who’s ever designed injection molded parts.
looking at the illustrated back of the envelope calculation, i was struck by how it glossed over the convenience…if i 3d print a dozen of something, i’m personally attending to my printer. it’s my own labor, and a lot of it. but if i send off to get a thousand of something injection molded, then all the labor (attending the injection machine) is embedded in the commodity price and i don’t have to think about it.
but then i appreciated the reminder, you can get 3d printing as a commodity service too! which really does make a nice ‘in between’ scale, where you can treat it as a commodity but at the same time get a different economy-of-scale than injection molding. pretty neat the diversity of services these days!
Nowadays the labour is probably 1-2 persons walking around in a hall with multiple injection moulding machines and checking if containers are full for some reason and doing tooling changes when production run is ready.
Not really.
While there are some fully automated injection molding facilities a significant percent of parts that are injected still require manual extraction. Unless you can gravity drop or robot extract, Its very common for shops to have an operator on each and every press pulling parts and ensuring the molds are clear between operations.
No.
Automatic ejection is a minimum.
When you have to manually extract a part, you almost invariably damage the part.
But it’s usually already bad (still soft when ejection pins/sleeves pushed etc).
Robots don’t extract the part, they hold the part when the ejectors kick it off the stick side.
No.
Robots and operators don’t eject the part, they EXTRACT the part when the ejectors kick it off the stick side.
Extraction is not ejection.
Ejection frees the part from the mold. Extraction removes the part from the machine.
Unless you can gravity drop or robot extract, Its very common for shops to have an operator on each and every press pulling parts and ensuring the molds are clear between operations.
Full ACK! The mold(s) is/are the key in this calculation.
I’d say 10k is an okish average per mold.
But you can get aluminium molds cheaper… and highly polished ones more expensive.
However surface quality and material properties are usually the thing that let you choose injection molding.
But 3d printing is a wide field on its own… SLS for example will give you completely different numbers.
Why do I keep seeing 10k for a mold? While I paid 1.5k for the last 3 mold I’ve had made, no sliders, 3 plates, steel, sand blasting and diamond finish, 30 to 90ct per part for 1k pcs, 45 days lead time from design to samples.
Of course you need to design injectable parts, very different from 3DP.
Contact plz!
I too would like to know where you’re getting those molds made.
Nothing fancy, Alibaba quote 10 injections molding subcontractor.
The key is to know the limits of injection: shrinkage, draft, surface finish, parting line, deep and narrow features, ejector marks and how to absolutely avoid sliders to keep price bellow 2k
Have been very satisfied with 2 ouf of 3 companies. (I own the mold, second run after 3 years and no rust 😅)
I would definitely do an article about it if editors are interested.
Describe it in a project on https://hackaday.io/
Put in all the details you think would help other folks, then submit it to the Hackaday.com tip line through the link in the project.
Just a FYI… I had got 2000 2-part injection parts done (2 halves with each being approx 4″x6″x2″ in size ) … so 4000 parts (UL-94V rated), included the mold (NAK80 Steel… good for 100000 pops), + shipping to Canada for $8K. The only additional cost was my importation fee ($300) + $80 to pick up the two pallets of parts at my local City depot. From start to finish took about 6 weeks (Ocean shipping which included a week delay because of CAN customs inspections). The parts received were outstanding and flawless with zero flaws and individually wrapped. The manufacturer quoted $7K… but I told them that I wanted them to make $ and to do an excellent job and so I paid $1K more ($8K total)
I would say shop around if you are being charged $10K just for a mold of average quality.
Size matters, a lot.
Bet you they only made a pair of insert sets for a mold base they own (hence the inserts are useless to you, unless you pay them) and they left the steel soft. 100k shots is low.
Remember: IM tooling can get ruined in 1 shot. e.g. 1 idiot attempting to clear stuck part with a screwdriver, ask me how I know.
Also: The inserts are rusting right now.
Do you own them?
Were they scrapped immediately?
The second order is where you will ‘find out’.
For all you know they were shot in Aluminum. 2000 shots is nothing. Aluminum is the right material for that length run. Cuts like butter, fast cycles.
10K won’t come close to getting you a full new mold base from IMS or similar western supplier.
Maybe for a tiny machine.
That’s Steel insert money, hardened. Competent American mold making job shop. Delivered into your hands. Not huge.
In my case, all I needed were the 2000 assemblies (4000 parts)… and so the approx per unit cost was $4…which include pretty much everything delivered to my City. If I needed more… than I just pay another $8K… as I feel the $4 per unit/assembly cost really cheap given the quality of what I received. However, YMMV. That said, your other comments are irrelevant for my needs.
I’d have to ask…How do you know the mold was made in steel?
As you say, you don’t really care.
Short runs like that are perfect for Aluminum tooling, could save you money next time. Spec it that way, save the Chinese guy one lie.
This is an apples to oranges comparison; you’d almost never design an injection-molded part anything like an SLA part, even if both used the same plastic. One is designed around draft angles, gates and parting lines, and the other around supports and layer orientation. You’d never try to work to both sets of constraints at once, especially given that some constraints (e.g. wall thickness) work oppositely.
At the concept stage, before you’ve drawn anything, you might be unsure which route to take, but if injection molding is even a question, then you should probably be doing it from the start. Otherwise, you could end up doing a ground-up redesign right when demand is taking off.
I’d also add, don’t sleep on vacuum forming, laser cutting, rotomolding, CNC machining and all the other ways to make things in small to medium volume.
We do lots of complex plastic design projects where we transition from 3d prints (1-2 PCs) to CNC (handful) to vacuum cast urethanes (for dozens) to injection mold (for anything more than that).
(3d print rarely has the finish or mat’l properties needed for anything but the most basic applications).
This guy has, I think, a better example of the unit costs and pricing considerations of 3D printing: https://www.youtube.com/watch?v=5koU93oZVC0
But how do you put a price on the sounds and smells of injection molding versus 3D printing?
Slant3D is a hack. Its embarassing that you even cite him as a source.