Camshaft Deburring And Cleaning: 66 Seconds For Two Parts At 3 mg

Overview

A camshaft is a long slender shaft carrying a series of lobed profiles that have been ground to a tolerance measured in hundredths of a millimetre. It is also, after drilling, a component with oil holes that intersect the journals and burrs that sit exactly where the oil has to flow.

Deburring it is therefore a different problem from deburring a block or a housing. The burr is small, but the surface it sits next to is the finished profile, and a brush or a cutter that removes the burr while touching the lobe has created a scrap part. Cleaning it is a different problem too, because the oil holes are small and the shaft cannot be flooded from outside.

The cell described here does both in one enclosure at 66 seconds for two parts, holding the part at or below 3 mg. Big Bird Industrial (formerly Shimada Big Bird Industrial) has been building cleaning and deburring systems for automotive powertrain components since 2001, and the configuration follows production lines for camshafts rather than a laboratory arrangement.

1. What Makes A Camshaft Different

Two properties separate a camshaft from other deburring work: it is slender, and its functional surface is difficult to approach without touching.

A Slender Part That Deflects

A camshaft supported at both ends deflects under its own weight and under any clamping force. That matters because deburring requires contact, and contact on a slender shaft changes the geometry it was ground to. Supporting it at more than two points, and applying tools with controlled force rather than position control alone, is what keeps the profile intact.

The Profile Is The Reference

On a block, the surface next to a burr is usually a general casting face with generous tolerance. On a camshaft, the surface next to the burr is the lobe, and the lobe is the reason the part exists. Every deburring method has to be judged on whether it can remove material from the edge without altering the adjacent surface.

2. Where The Burrs Actually Sit

Camshaft burrs concentrate at a small number of locations, and each one needs a different treatment.

Oil Hole Intersections

Every drilled oil hole exits into a journal or a lobe flank, and the exit edge carries a burr on the inside of the hole. That burr is the most damaging one on the part, because it breaks away into the oil flow and reaches a bearing surface. It is also the hardest to reach, because it sits inside a hole that may be only a few millimetres across.

Lobe Edges And Keyways

The flank edges of a ground lobe carry a fine burr from grinding, and a keyway or a sprocket register carries a heavier one from milling. The fine burr can be removed with a brush; the heavier one needs a tool, and the tool needs to approach the edge from a direction that does not touch the flank.

3. Deburring Without Touching The Profile

The method has to remove material from an edge while leaving the adjacent surface untouched, and on a camshaft those two surfaces are millimetres apart.

Force Control Rather Than Position Control

A robot driven to a position will push a brush into the lobe by whatever the position error happens to be. A robot with force control follows the edge with a defined contact force, which keeps the brush on the burr regardless of where the ground surface actually is. On a slender part, that difference is the difference between a deburred camshaft and a scrapped one.

Wet Deburring In The Same Cell

Deburring inside the cleaning cell, with the operation flooded, captures the fragments in liquid rather than releasing them into the air. On a camshaft that matters more than on a block, because the fragments are fine and the oil holes are close to where the brush is working.

4. Cleaning The Oil Holes

A camshaft oil hole is small, often angled, and exits onto a surface that has to stay clean. Spraying the shaft from outside wets it without flushing the holes.

Flushing Through The Hole

The effective approach is to deliver liquid into the hole so that it flows out through the exit, carrying the burr fragment with it. That requires a nozzle that seals against the entry, or a lance that enters it, and it requires the pressure to be high enough to move a fragment against the wall of a small bore.

Why The Order Matters

Flushing before deburring is wasted work, because the deburring creates the fragments. Flushing after deburring but before rinsing leaves the fragments in the oil hole until the rinse dilutes them. The sequence that works is deburr, flush, rinse, dry, with the flush using separately filtered liquid so that it does not return the previous part's debris.

5. The 66-Second Two-Part Cycle

The cell runs two camshafts per cycle at 66 seconds, holding the part at or below 3 mg. Two parts per cycle is not an accident of the machine size: it balances the deburring time against the cleaning time, so that neither stage waits for the other.

Why Pairing Works On A Slender Part

A camshaft occupies little volume relative to its length, so a chamber sized for one is mostly empty. Loading two, supported at their ends and separated, uses that volume without increasing the chamber, which improves throughput per unit of enclosure rather than per unit of energy.

What Sets The 66 Seconds

The cycle is set by the deburring motion, not by the wash. A brush following several lobes and several oil hole exits on two shafts is a long program, and the wash stages are shorter than the deburring stage. That distribution is why a camshaft cell looks different from a housing cell, where the wash dominates.

6. Verification

Verification on a camshaft has two parts that are often confused: the burr and the cleanliness. A part can have no burr and fail the mass limit, because the deburring fragments are still inside the oil hole. A part can pass the mass limit and still carry a burr that will break away later.

The practical verification is a visual check of the specified edges under magnification, combined with a measurement of the oil hole interior that confirms flush passed through. Checking only the outside of the shaft tests the surface the customer will never see. On a camshaft the two checks are also performed at different times: the edge check can be done on the first part of a batch, while the flush check is a sample from the middle and the end, because a brush that wears during the batch changes what reaches the holes.

Frequently Asked Questions

Can Camshafts Be Deburred In The Same Machine As Blocks?

Rarely in the same cycle. A block cell uses high pressure and large flow on a heavy part, while a camshaft needs force-controlled tooling on a slender one. They can share a building and a filtration philosophy, not a chamber.

How Is The Lobe Protected From The Brush?

By controlling contact force rather than position, and by choosing a brush whose stiffness is low enough not to mark a ground surface at that force. The two settings are chosen together.

Is 3 mg Realistic For A Part This Long?

It is realistic when the oil holes are flushed rather than sprayed, and when the rinse circuit is kept separate. Most failures on camshafts come from the holes rather than from the outside surface.

What Limits The Cycle Time?

The deburring program. Following several lobes and several hole exits with a controlled tool takes longer than washing the same part, which is the opposite of a housing line.

Conclusion

A camshaft is deburred against a finished surface rather than a rough one, and that is what constrains the method. Force-controlled tooling, wet operation and a flush through each oil hole are the three decisions that make a combined cell work.

The specification should name the edges to be deburred, the oil holes to be flushed, the cleanliness limit and the cycle unit. A camshaft cell quoted as two parts per cycle at 66 seconds is only comparable when the second figure is stated with it. So is a cell quoted at three milligrams, because the region that figure applies to is as important as the value. A figure taken on the shaft exterior describes a different part from one taken inside the oil holes.