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.
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.
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.
I smell MBA.
Does anybody else smell MBA?
(Goes to find pitchfork and torch.)