High precision threading performance

CoroMill® 325 – thread whirling

Designed for the medical industryThe growing use of medical bone screws, implants and other micro-components creates a need for techniques that pro-duce special thread forms quickly and at high tolerances.

New thread whirling inserts and holders from Sandvik Coromant meet this need for a large number of sliding head machine types. They can thread long, slender components from rough stock at high speeds, without the need for a dedicated thread whirling machine.

No bending on long slender componentsMulti-inserts apply even cutting pressure on long, slender components – creating high-precision thread forms without bending.

Chip controlChip control is superior to single-point threading, enabling more continuous and productive machining.

Increased productivitySingle-pass machining from stock diameter reduces cycle time by minutes.

Faster set-up timesReduce downtime by eliminating the need to match rough and finish insert forms and special support devices.

Increased tool lifeThread whirling inserts have stronger cutting edges than single-point tools.

Cost savingFinishing treatment is not required after thread whirling, unlike single-point threading.

Deeper threadsDeeper thread forms (such as Acme) can be achieved more easily.

The thread whirling process

The spindle unit is

tilted to the helix

angle of the thread

A thread whirling ring with inserts on the inner diameter rotates around a cylindrical component to cut the thread. The smooth, tangential cutting action minimizes cutting forces to give high metal removal rates.

1. Mount the whirling ring onto the spindle unit

2. Tilt the spindle unit to the desired helix angle of the screw

3. Program the ring off-centre, in relation to the thread diameter

4. Rotate the whirling ring and component in the same direction (climb milling) for optimum tool life

5. Rotate the workpiece at a slower speed, determined by its diameter and the lead of the thread being made

6. Coordinate movement of the whirling ring with the rotation of the component for best surface and productivity. (chip thickness is determined by the feed rate of the whirling ring)

The spindle and ring rotate i

n

the same direction to achiev

e

climb milling and productivi

ty

Off-centre positioning

Easy tool set-up saves time The thread whirling ring can be quickly attached outside the machine, in a clean environment.

1. Insert the ring over the spindle screw

2. Turn the ring anticlockwise to the bottom position

3. Tighten the ring screw

For standard threadsSpecially-formed inserts for thread whirling are designed to create HA and HB thread forms. These threads have the specific dimensions and tolerances needed for bone screws and other medical implants.

HA thread form

HB thread form

HA and HB threads

correspond to ISO

5835-1991, for

medical screws

325-12AP40-16M Citizen PCM325-12AQ40-16M Citizen Jarvis325-12BB40-16M Star Star325-20CC52-16M Tsugami Tsugami325-12DD40-16M Tornos Tornos

325R16-150HAF01, GC1105325R16-175HAF01, GC1105325R16-175HBF01, GC1105325R16-275HBF01, GC1105

Whirling ring codes MTM Spindle producer Insert code and grade

Wide range of sliding head machine types Insert assorment

Designed for medical machiningAll Sandvik Coromant thread whirling inserts are available in GC1105 – the first-choice grade for medical machining. GC1105 offers sharper edges and a burr-free component surface:

- Dedicated to machining stainless steels and titanium

- Ideal for stable applications for all materials in sliding head machines

- Enables longer, more continuous runs, with higher productivity

Choose your own thread!

Order special insert

s for any thread p

rofile;

and rings for other

spindle units. See y

our

Sandvik Coromant r

epresentative for m

ore

information and to

make your request

for

non-standard rings a

nd inserts.

Cutting data for ISO S materialsvc 40–60 m/min (130–200 ft/min)

hex 0.02–0.10 mm (.0008–.0039 inch)

Max fz 0.05 mm (.0020 inch)

For screw diameters 3–10 mm

(.12–.40 inch)

Performance test

Material: Titanium Ti-6AI-4V ELIThread dia, mm (inch) 3.5 (0.139)Length, mm (inch) 25 (0.984)Thread profile: HA4Pitch, mm (inch) 1 (0.04)Machine tool: Tsugami 14Components/year: 500 000

Cutting datahex, mm (inch)vc, m/min (ft/min)No. of passesCycle time, minNo. of components

Result: 511% increase in components produced

In this application, the superior tolerance of the Sandvik Coromant ring-and-insert combination resulted in a 500% increase in the number of bone screws produced, compared to a competitor whirling solution.

Competitor Sandvik Coromant0.04 (0.002) 0.04 (0.002)26 (85) 26 (85)1 10.6 0.6215 1100

M

S

M S

M S

M S M S

A complete bone-screw solution

Thread made by thread whirling

Precision tooling for the medical component industry.

Machine: CNC sliding head machine

Main spindle: 10,000 rpm Sub spindle: 8,000 rpm

Material: Stainless steel – Sandvik Bioline 316 LVM

Titanium – Ti6Al4V ELI

Holder: QS-SDJCR 1212E 07 Insert: DCET 070201-UM, GC1105 vc, m/min 50–100 40–60

(ft/min) 160–330 130–200fn, mm/r 0.03 0.03

(inch/r) .0012 .0012ap, mm 0.3–1.0 0.3–1.0

(inch) .012–.039 .012–.039

MAI

N S

PIN

DLE

SU

B S

PIN

DLE

vc = Cutting speed fn = Feedap = Cutting depth

Turning front of head

Turning back of head and parting

Holder: QS-RF123E11-1212B QS-SMALR 1212E3 Insert: N123E2-0200-0002-GF, H13A MACR 3200N, GC1025 vc, m/min 50–75 40–50

(ft/min) 160–250 130–160fn, mm/r 0.04 0.04

(inch/r) .0016 .0016

Drilling of head

Drill: R840-0250-50-A0B, GC1020 vc, m/min 30–50 20–40

(ft/min) 100–160 70–130fn, mm/r 0.03–0.06 0.02–0.04 (inch/r) .0012–.0024 .0012–.0024

Holder: CXS-A0750-04 Insert: CXS-04T098-10-2206R, GC1025 vc, m/min 50 40

(ft/min) 160 130fn, mm/r 0.02 0.015 (inch/r) .0008 .0006

Clearance turning of bottom of hole

The smarter choice for medical machiningContact your local Sandvik Coromant representative for more information about thread whirling and other advances in medicine (including inserts for cobalt-chromium implants) or check out www.sandvik.coromant.com.

Sandvik BiolineMaterials technology for the medical industry and one of today’s most advanced R&D programs. Working together with Sandvik Coromant for your complete clinical component needs. www.smt.sandvik.com/medical

Your local Sandvik Coromant distributor:

Round inserts for

machining titanium and

cobalt-chromium hip-joint

implants

CoroMill® 325- Standard tools for threading bone screws and implants

- Also for non-standard thread forms

- Optimized for titanium and HRSA

- Compatible with many sliding head machines and spindles

- Fast and effective performance

Head office: AB Sandvik Coromant SE-811 81 Sandviken, Swedenwww.sandvik.coromant.com E-mail: info.coromant@sandvik.com

C-1040:092 ENG/01 Printed on recycleable paper. Printed in Sweden, AB Sandvikens Tryckeri. © AB Sandvik Coromant 2010.07