There are instances where we are asked to CNC machine parts, product or a
prototype that are either hard to machine, too complicated
geometrically, will not yield great accuracy or simply cannot be
machined. What do we do? For these scenarios, 3D printing the parts can
be a great solution. So why not substitute CNC machining with 3D
printing every single time? Well, there are advantages and
disadvantages, pros and cons for each machine and process. So, which one
is best for our needs? In which circumstances do we prefer one over the
other? And is there another solution that might combine these two
together to create a combo part?
The basic difference between
the two processes is that with CNC machining we are reducing material as
we start with a foam block for example, carving it away; while with 3D
printing we are layering on and adding material until we receive the
final product, therefore called additive manufacturing.
The 3D
printer uses the same materials that make up the part it is creating,
for instance ABS PLA and nylon, but it cannot switch between materials,
whereas in CNC machining we can use several types of materials, often
adding additional materials at the end. However, machining can be messy
- Sometimes we need to use a dust collector while operating a CNC
router machine to catch all that excess made in the drilling, carving
and milling process, while there is less waste material produces in
printing and the whole process is less noisy.
CNC machining can be
more precise providing more accuracy because the machines have a higher
tolerance for heat. It can also result in a much smoother polished
surface finish given the materials to be machined. 3D printers can
actually distort a part, bend and warp if using too much heat on the
layered material, so if exceptional smoothness is required the 3D
printing will fall short.
3D printing is generally an easier
more convenient process and not as labor-intense as CNC machining, since
with machining we need to program, write a G-Code, set up different
tools and speed, decide on cutting path and clean up after. However, the
part size plays a role, as larger parts take longer to be printed
adding layer by layer. Overall, 3D printing can assist in some cases of
prototyping of high geometric complexity where the router tool cannot
reach inside the shape.
3D printers can only use the area of the
printer bed itself to fabricate the parts. Therefore, if large scale
parts are needed they might not be able to fit in there. It is also not
recommended for mass production as the materials are much more expensive
and take much more time to fabricate. Therefore, 3D printing is more
appropriate and more cost-effective for low volume production.
CNC machining can rarely run unattended and requires skilled operator,
while with 3D printing we can easily run the process unsupervised and it
requires minimal training for its operator. However, CNC machining is
an older practice (started in the 40’s) and currently still has a
stronger position in the manufacturing industry. 3D printing is
relatively new and still evolving to be more useful and adaptable and
still cannot be a full replacement for machining.
In summary,
the most appropriate technique to use will be determined by the
material, geometric complexity, manufacturing volume and our budget. As a
general guidance, we would switch to 3D printing mostly if fast
turn-around in critical, if the part is too complex to be machined, for
prototyping small volumes and if we need to use certain materials that
cannot be easily machined.
Having named most of the pros and cons
for each technique, apparently there is a good solution that actually
combines the two together to create one part. We often machine parts of
the desired product using a CNC router, while fabricating other small
yet more complex parts in the 3D printer, we then glue all parts
together to make one unit. Another option is then to coat all glued
combined parts with hard coat such as Polyurea, Styrospray or epoxy,
then smooth and paint them. That way we both save time using the CNC
machining process as well as being able to manufacture more complex
parts combining the best of the two worlds together to create a hybrid.
http://bus.gov.ru/forum/user/profile/89299.page
https://social.saratov.gov.ru/services/forum/index.php?PAGE_NAME=profile_view&UID=118264
http://www.minstroy.saratov.gov.ru/communication/forum/messages/forum2/topic79/message193/
http://drohobych-rda.gov.ua/user/ecyopett/
http://old.kam-pod.gov.ua/user/ecyopett/
http://ipi.tspu.edu.ru/user/ecyopett/
http://kttd.udpu.edu.ua/index.php?subaction=userinfo&user=ecyopett
https://portal.edu-bko.gov.kz/?page_id=97&view=topic&id=13&part=1#postid-23
http://www.iod.gov.ua/profile.php?lookup=1244
http://www.ved.gov.ru/forum/?&action=showreplies&fid=21&topic=6919
http://kazng.gov.kz/kz/component/kunena/suggestion-box/16-obmennik-bitkoin.html
http://www.volodrada.gov.ua/index.php/forum/kultura/329-obmennyk-bytkoyn
http://imfl.sci.pfu.edu.ru/forum/index.php?action=profile;area=summary;u=597243
http://torgi.gov.ru/forum/user/profile/897280.page
http://monrda.gov.ua/index.php/forum/dobro-pozhalovat/89680-kupyt-kryptovaliutu#61320
No comments:
Post a Comment