Methods for forming thin wall tubing into a tightly-coiled helical duct comprise selecting a thin wall tube with an outside tube diameter and a wall thickness that is less than 15% of the outside tube diameter; and bending the thin wall tube to form the tightly-coiled helical duct so that an outside duct diameter of the tightly-coiled helical duct is less than four times the outside tube diameter.

A bending machine has a main spindle which supports a die. There are two counter dies each mounted on a working arm which rotate about the main spindle. The working arms are driven by link arms which are acted on by a translational drive. There is versatile three-point bending caused by three die points, two on the working arms and one on the die support shaft. The working arm drive includes a translational component which extends through the die support shaft, and which is connected to the link arms. This achieves excellent symmetry and compactness.

A bending machine has a main spindle which supports a die. There are two counter dies each mounted on a working arm which rotate about the main spindle. The working arms are driven by link arms which are acted on by a translational drive. There is versatile three-point bending caused by three die points, two on the working arms and one on the die support shaft. The working arm drive includes a translational component which extends through the die support shaft, and which is connected to the link arms. This achieves excellent symmetry and compactness.

Tightly-coiled helical ducts for centrifugal air separators may be formed with the tools and methods disclosed herein. A helical coil toolset includes a helically grooved mandrel and an entry block. The helical groove of the mandrel has a small helix inside diameter relative to a width of the helical groove. The entry block has a guide channel to guide a tube to the helical groove and a mandrel channel to receive the mandrel. Methods include forming tubing into a tightly-coiled helical duct by filling a tube with fine particles, positioning the tube in the helical groove of a helically grooved mandrel, fixing the tube relative to the mandrel, assembling an entry block around the tube and around the mandrel, and bending the filled tube around the helically grooved mandrel into the tightly-coiled helical duct by rotating the mandrel relative to the entry block.

Tightly-coiled helical ducts for centrifugal air separators may be formed with the tools and methods disclosed herein. A helical coil toolset includes a helically grooved mandrel and an entry block. The helical groove of the mandrel has a small helix inside diameter relative to a width of the helical groove. The entry block has a guide channel to guide a tube to the helical groove and a mandrel channel to receive the mandrel. Methods include forming tubing into a tightly-coiled helical duct by filling a tube with fine particles, positioning the tube in the helical groove of a helically grooved mandrel, fixing the tube relative to the mandrel, assembling an entry block around the tube and around the mandrel, and bending the filled tube around the helically grooved mandrel into the tightly-coiled helical duct by rotating the mandrel relative to the entry block.

A metal extrusion and nodes based structure is provided. The structure comprises one or more arc members connected by one or more node members, wherein the arc comprises (i) a wing feature which is configured to mate with one or more non-structural components, (ii) an internal passage feature which is configured to be inserted into a connecting feature of the corresponding node member, and (iii) one or more keying features formed from a mating interface with the corresponding node member.

A metal extrusion and nodes based structure is provided. The structure comprises one or more arc members connected by one or more node members, wherein the arc comprises (i) a wing feature which is configured to mate with one or more non-structural components, (ii) an internal passage feature which is configured to be inserted into a connecting feature of the corresponding node member, and (iii) one or more keying features formed from a mating interface with the corresponding node member.

A metal extrusion and nodes based structure is provided. The structure comprises one or more arc members connected by one or more node members, wherein the arc comprises (i) a wing feature which is configured to mate with one or more non-structural components, (ii) an internal passage feature which is configured to be inserted into a connecting feature of the corresponding node member, and (iii) one or more keying features formed from a mating interface with the corresponding node member.

A metal extrusion and nodes based structure is provided. The structure comprises one or more arc members connected by one or more node members, wherein the arc comprises (i) a wing feature which is configured to mate with one or more non-structural components, (ii) an internal passage feature which is configured to be inserted into a connecting feature of the corresponding node member, and (iii) one or more keying features formed from a mating interface with the corresponding node member.

A metal extrusion and nodes based structure is provided. The structure comprises one or more arc members connected by one or more node members, wherein the arc comprises (i) a wing feature which is configured to mate with one or more non-structural components, (ii) an internal passage feature which is configured to be inserted into a connecting feature of the corresponding node member, and (iii) one or more keying features formed from a mating interface with the corresponding node member.