CNC Machining question

Hey do we have any one on here that works with CNC machining or has general knowledge of if all.

Basically I need to know if there is any difference with getting a component (non motorcycle related) done with CNC vs Casting. i.e pros and cons of both processes.

@National_Treasure knows everything.

CNC vs Casting is something I know very little of. Factors I’d consider would be quantities, cosmetic finish, dimensional accuracy etc. I guess the bottom line is if its for a one off or its a particularly intricate part machining will win the day.

I’d say any cast part like a fork yoke would still need machining to get the precision of finish for any mating surface, so it’s usually cheaper/easier to start from the beginning with machining.

Plus any part machined from a billet would have less likelihood of hidden voids or weakness of a cast part (depending on quality of foundry).

Oh ok, that sort of falls in line with all the information I have been able to gather so far. Cast for high volume but finish off with machining to get within tolerance. Just wasnt sure if one gives a less overall quality(strength, accuracy, finish). I cannot help but think that any process designed for high volume and quick turnover naturally introduce a higher possibility of imperfections.

@me_groovy by void, I am guessing you mean air pockets?

yeah, it’s what people are usually scared about with using chinese levers on bikes.

Hi there, I am familiar with both processes. In a general point of view casting provides less hardness and elastic properties and is a cheaper way for producing parts by melting the material in a pre-shaped cast. Casting, as me_groovy says, can hide internal flaws. On CNC you can use treated or raw materials produced with almost the final strenght properties, more pure and flawless, e.g. extrusion on aluminium parts. Final shape can be obtained both cases with CNC.

Thanks for the info. Is there anything a manufacturer should\can do to reduce the likely hood of flaws in the casting process ?

Yes, casting process can be carried out controlling different parameters: purity of the material, temperature control, cast design, etc. Some flaws can be just cracks due temperature spots during casting, inclussions of unwanted contamination and bubbles inside when material schrinks as temperature decreases