Corrugated tube

The white ribbed tube that carries pellets up to the Hopper. The Vacuum pump draws pellets through it from whatever container holds the material — a plain pellet bucket, or the D1 dryer standing next to the printer.

Drawing from a D1 dryer

When the source is a D1, the tube clamps onto the pellet gate under the tank — a pickup filter that stops pellets dropping into the tube by gravity while letting air in, since it is the airflow that carries the pellets. Above it sits a manual guillotine, closed while drying and opened when a print starts. See Pellet gate and guillotine.

Function

• Transports pellets from the material source to the hopper via vacuum suction
• Flexible enough to route around the machine
• Ribbed design allows bending without collapsing the bore

The rule that matters: no gravity drop

Never let material fall through the tube under its own weight

Route the line so that pellets can never travel downward by gravity anywhere along it. Wherever they can, they accumulate — the tube fills with material and blocks.

This single rule replaces any fixed maximum length. What matters is the shape of the run, not how many metres it is:

Requirement	Why
No descending sections	Pellets fall into them and pile up until the line is plugged
No dips or U-bends	Same failure, at the bottom of the dip
Always rising toward the hopper	Material only moves when the vacuum moves it, never on its own
Airtight seal at the hopper	Even a small leak breaks the suction

How the feeding line is arranged

The feed line is three sections, not one tube. Each section is a different type:

#	Section	Type	Role
1	From the dryer	White corrugated	Leaves the pellet gate under the D1 dryer tank, clamped on with a worm-drive hose clamp
2	The long run	Smooth rigid grey pipe	The static middle section. Being rigid it holds the bore open and stops the line sagging into a belly
3	To the extruder	White corrugated	The moving section — flexes to follow the gantry and the extruder

From How the G1 Automatic Feeding System works — 2:15

Note

The corrugated tube is white. It photographs grey under workshop lighting, which is why it sometimes gets described as a grey tube.

Both corrugated sections and the rigid pipe are part of the same line — a machine is not “using the wrong tube” because it has both.

The feed line end to end. Material moves left to right along each row; the accent arrow marks where air enters, which is what actually conveys the pellets.

The extruder cabling does not run in a tube

Nothing corrugated on the G1 carries wiring. The extruder’s cables — thermistors, heater bands, motors, level probe — land on the breakout board on the extruder carriage, and from there they travel to the panel box through the drag chains, one per axis: X → Y → Z.

So every corrugated tube you see on the machine belongs to the feeding line.

Securing the moving section

The corrugated section that follows the extruder is secured with a zip tie at the frame end (assembly video, 13:48) so its slack cannot snag the gantry. If you re-route it, put the tie back.

The tube-to-hopper joint

The joint between the corrugated tube and the hopper is the first place to look when suction fails. Air leaks here mean the vacuum cannot build enough differential pressure to lift pellets.

What to check when suction is weak:

1. Check that the clamp is tight
2. Check that the gasket (rubber seal inside the fitting) is intact and seated correctly
3. Compress the gasket slightly by hand — it should feel firm and springy, not flat or cracked
4. Replace the gasket if it shows any compression set (permanently flattened)

See Hopper suction problems for the full diagnostic flow.

Routing guidelines

• Run straight and rising from the material source to the hopper, with no descending section anywhere
• No dips — a low section is where pellets settle and plug the line
• Keep the run short — not because of a length limit, but because a short run is easier to keep rising
• Place the material source close to the machine

Why the shape matters more than the length

Pellets are lifted by air velocity, not suction force alone. Anywhere the line stops rising, material settles instead of travelling — and once a plug forms, airflow drops and the plug grows.

Pellet types

The feeding line handles ordinary pellets without trouble — standard, cylindrical or regular shredded material all travel fine as long as the line is routed correctly. Only the two ends of the size range cause trouble:

• Large, irregular flakes — bigger than about 7–8 mm — interlock and jam in the line
• Dust can be drawn into the vacuum or clog it

Recycled material of one particular kind is the other exception:

Recycled material with strings or microplastic

Recycled pellets that contain strings, threads or microplastic clog the filter. If you run recycled material of that kind, expect to clean the filter regularly.

Replacement

If the tube is kinked, cracked, or permanently deformed, replace it. The tube is standard corrugated pneumatic hose (verify the inner diameter matches the fittings). Available from Ginger support or industrial hose suppliers.

Related notes

• Hopper suction problems — main troubleshooting guide for the feeding system
• Hopper — the container the tube connects to
• Vacuum pump — the suction source
• SmoothFlow — lubricant that helps transport difficult pellets