YYT 1506-2016 Surgical implant metal bone screw rotation torque test method

Surgical implant metal bone screw rotation torque test method Surgical implant metal bone screw rotation torque test method 1 scope This standard is used to measure the torque
required when a metal bone screw (hereinafter referred to as "borer") is screwed out of a standard material.
The results obtained using this standard are not directly related
to the rotational torque required when the screw is screwed into the human bone.
The purpose of this standard is only to confirm the consistency
of the tested product.
2 Normative reference documents The following documents are applied
to this document.
Where a dated reference is made, the date-only version applies to this document
.
The most recent version of an undated reference applies to this document
.
JJG 269 Torsion Testing Machine Verification Regulations 3 Equipment 3.
1 Test Device The device shown in Figure 1 can be applied to the screw-in and spin-out torque test
.
The test setup shall be able to fit
with the test block, test block fixture, drill sleeve, and drill sleeve clamping fixture described in accordance with ASTMF1839 material.
The test device shall have sufficient stiffness so that no deflection or deformation
will occur under test loading conditions.
3.
2 The torque transducer can convert the applied torque into a converter that can continuously record the electrical signal, and calibrate it within the range used in the test, including YY/T 1506--2016, including clockwise and counterclockwise directions
.
3.
3 Torsion angle sensor can convert the torsion angle into a converter that can continuously record electrical signals, and calibrate according to JJG269 within the range used in the test, including clockwise and counterclockwise directions, with an accuracy of 0.
3°
.
3.
4 Data Logging Equipment The data recording equipment shall be able to continuously record the torque and rotation angle, the torque shall be Newton - meter (N.
m) and the rotation angle shall be in degrees (°).

The torque resolution should reach 10%
of the maximum measured torque.
The angular displacement scale should be sensitive enough to record and display at least 4 revolutions
.
3.
5 Drill sleeve drill sleeve is used in conjunction with the test device and can be replaced
with materials that comply with ASTM F 1839.
The drill sleeve should have sufficient length and stiffness to ensure that the sample rotates vertically to the test block
.
The inner diameter of the drill sleeve should be sized in such a way that the specimen is subjected to minimal frictional resistance
between its outer diameter and the inner diameter of the drill sleeve.
Grinding drill sleeves are not reusable
.
3.
6 The test block fixture can be used with the clamp or fixture of the test device
.
The clamp should be able to keep the pre-drilled guide hole in the test block collinear
with the test sample.
The fixture avoids deforming the test block during clamping or testing.
3.
7 Test sample The test sample should be a final product that is long enough to penetrate the drill sleeve and test block
.
3.
8 The test block shall be made of a uniform material in accordance with ASTMF 1839 The foam density that the user can choose for this test, more information can be found in 8.
6.
2 of ASTMF 1839.
According to the requirements of the guide hole described in 3.
9, the minimum size of the test block surface shall be greater than 10 times
the diameter of the screw.
The upper and lower surfaces of the test block should be flat, polished and parallel to each other (deviation +0.
4 mm) to ensure that its upper surface is perpendicular
to the screw centerline when fixed in the fixture.
The test block should be square or other shape
that ensures that the test block is free of relative movement and deformation during the holding or testing process.
The thickness of the test block should not be less than 4.
8 mm
.
3.
9 The guide hole
in the test block should be pre-drilled in the test block before screwing in and out of the test block.
The guide hole ruler should be specified
by the manufacturer of the end nail to be measured.
If specified by the screw manufacturer, the guide hole should be tapped
with a tap of the specified size before the test.
The guide hole should be drilled perpendicular to the surface of the test block, and the hole should be straight and should not be conical.
Flare, bucket-shaped, etc
.
If there are multiple guide holes on the surface of the test block, each hole should be far enough away from the edge of the test block to ensure that the test does not cause deformation
of the edge of the test block.
The spacing should be at least 5 times
the diameter of the screw.
When the test block is installed to the test setup (see Figure 1), the guide holes, screws, and screw drive fixtures should be on
the same axis.
4 Test samples should be randomly selected
from each batch or process volume according to ASTME122.
5 Testing instrument PBSC-RP30 bone screw performance tester 6.
Test steps screw in torque and screw out torque A The sample is installed in the test device shown in Figure 1, the sample is screwed into the test block using a matching tool of appropriate size, and the torsion testing machine is used to apply torque to the screw head
at a speed of 3r/min.
The screw-in torque is the maximum torque
recorded in the first 4 revolutions of the sample.
The counter-rotating screw measures the screw-out torque, which is the maximum torque (N.
m)
recorded by 4 revolutions in the test block.
An axial load of no more than 11.
17N is always applied during screw-in and spin-out to ensure that the drive fixture is in the
screw head.
If a larger axial load is used, the axial load
used should be documented in the report.
Measure axial loads
using suitable methods.
7.
The report report should contain the following content for each specimen (all values in the report are in international SI): a) screw information The national standard industry standard or ISO standard number
that the screw complies with 。 If the criteria are not met, the screw head form, thread form, maximum diameter/bottom diameter, pitch, full screw length, nail head and rod part (screw removal of the unthreaded part of the head) length and screw type should be provided; b) the chemical composition of the screw; c) surface treatment form; d) Rotating torque: 1) required axial load; 2) spin depth (can be obtained by calculation or measurement); 3) The provisions on whether the guide hole is tapped, if tapped, the report should include the tap size, tap diameter and tapping depth; 4) screw-in speed (if not in accordance with the provisions of Chapter 5); e) Screw-out torque: 1) Required axial force; 2) Screw-out speed (if not in accordance with Chapter 5) ;D description of the test block material: Grades in ASTM F 1839, drill sleeve materials that do not comply with ASTM F 1839 shall be reflected in the report: 1) trade name; 2) Ingredients; 3) density; 4) tensile strength; 5) Compressive strength; 6) Shear strength
.