Guides / Cost

When Five Axis Machining Pays for Itself on a Case

September 21, 2026

Five axis machine time costs more per hour than three axis. It can still make your case cheaper, and understanding when is worth a few minutes because it changes how you draw the part.

What the extra axes actually do

A three axis mill moves the cutter in X, Y and Z. The tool always points the same way, so it can only reach what is facing up. To machine another face, the part comes out, gets refixtured and goes back in. That is a setup.

A five axis machine adds two rotations, so the part can be tilted and turned under the tool. Faces that would have needed separate setups can be reached in one.

The cost of a machined part is dominated by setups and cycle time, not by which machine did the cutting. That is the whole economic argument.

Where the saving comes from

Every setup carries:

• Fixture or soft jaw design and machining
• Setting and proving the operation
• An alignment error opportunity
• Another chance to mark a cosmetic surface while handling the part

Collapse five setups into three and you remove two fixtures, two set ups and two chances to damage the most expensive surface on the part. On a run of two hundred, that can outweigh a higher hourly rate comfortably.

On a run of ten it often does not, because the fixture saving is spread across too few parts.

Designs that genuinely want five axis

Angled side faces. A case with walls that lean rather than standing vertical is awkward on three axis and natural on five.

Continuous curved surfaces. A top case with a sculpted profile that flows around a corner is far cleaner cut with the tool able to tilt into the surface.

Undercuts. Anything a straight down cutter cannot see. These are either five axis features or three axis features with extra setups and specialist tooling.

Chamfers and edge breaks on multiple planes. Doing them in one operation keeps them consistent, which shows on a cosmetic part.

Designs that do not

A conventional rectangular case with vertical walls, a flat top, internal pockets and tapped holes is a three axis job. Adding five axis to it buys nothing except a bigger number on the quote.

Plates are three axis, always. So are most weights.

What this means for your drawing

Two practical points.

Do not specify the machine. Specify the result: tolerances, cosmetic zones, finish, and what has to agree with what. A shop told which machine to use will quote defensively and you lose the benefit of its own judgement about the cheapest route to the same part.

Do tell the shop which features must agree with each other. If the plate pocket and the screw bosses have to be in the same coordinate frame, say so with a datum and a position tolerance. That is the information a shop uses to decide whether those features should be cut in one setup, which is the decision that actually saves you money. There is more on this in which tolerances actually matter.

Ask the question the useful way

When you get quotes back, a good question is not “do you use five axis”. It is “how many setups is this part, and what is driving that number”.

The answer tells you two things. It tells you whether the shop has actually thought about your part, and it very often tells you about a feature in your model that is expensive for a reason you did not intend. A designer who hears “the undercut on the rear face adds a setup” can go and ask whether that undercut is worth it.

That single conversation has taken more money out of keyboard case quotes than any machine choice ever has. If you want to start it, send the model and the drawing and ask for a setup count with the price.

Setups are one of the cost lines in our guide to keyboard case manufacturing cost.

Frequently asked questions

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