Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C29/00—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides
  • C22C29/02—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides
  • C22C29/06—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds
  • C22C29/08—Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides based on carbides or carbonitrides based on carbides, but not containing other metal compounds based on tungsten carbide

Definitions

• the present invention relates to a tool for drill - ing/routing of printed circuit board materials.
• the binder phase By alloying the binder phase with Ru in combination with the use of fine grained Co-powder the properties have been improved .
• Cemented carbide containing Ru as binder phase alone or in combination with the conventional Co and/or Ni is known in the art.
• AT 268706 discloses a hard metal with Ru, Rh, Pd, Os , Ir, Pt and Re alone or in combination as binder phase.
• US 4,574,011 discloses a hard metal composition for ornamental purposes with a binder phase of Co, Ni and Ru.
• GB 1309634 discloses a cutting tool with a Ru binder phase.
• GB 622041 discloses a hard metal composition a Co+Ru binder phase.
• the routing of Printed Circuit Board materials requires a wide range of properties from the tool material in order for it to perform successfully. These include a hardness in excess of 2000 HV, a resistance to edge chipping that is best defined by a fracture toughness in excess of 8 MPam 1/2 , a resistance to chemical attack from the resins included in printed circuit boards and a sharp as possible a cutting edge. Some of these requirements conflict, for instance the high hardness tends to mean a reduced edge toughness .
• the new products for this application can, therefore, require a reduced WC grain size to produce a higher hardness with reduced tough- ness . However, if this is combined with an increase in cobalt content an increased toughness can be achieved for the same hardness . This also results in a sharper cutting edge, which is required.
• the invention is primarily concerned with the addi- tion of ruthenium to submicron grades of cemented car- bide.
• the levels of addition vary between 5 and 35, preferably between 15 and 30, wt-% of the binder content with the best results obtained at about 25 wt-%.
• the cobalt used should be of the fine grain size cobalt powder having deagglomerated spherical grains of about 0.4 ⁇ m average grain size and with a narrow grain size distribution.
• the cobalt powder is polyol cobalt.
• the cobalt contents to which this addition can be made should vary from 5-12%, pref- erably 5-8.
• the average WC grain size shall be ⁇ 0.8 ⁇ m, preferably ⁇ 0.4 ⁇ m.
• the cemented carbide of the invention is preferably a straight WC+Co grade but it may also contain ⁇ 5 wt-% gammaphase.
• VC+Cr3C2 In order to obtain the submicron WC grain size VC+Cr3C2 is added. Because the Ru also acts as a mild grain growth inhibitor an addition of ⁇ 0.9wt% VC+Cr3C2 is generally satisfactory. Particularly good results are obtained if the VC/Cr3C2 ratio in wt% is 0.2-0.9, preferably 0.4-0.8, most preferably 0.6-0.7.
• sin- tering is performed using gas pressure sintering also referred to as sinter-HIP.
• the invention also relates to the use of a cemented carbide with submicron WC grain size and with a binder phase containing 10-30 wt-% Ru as a tool for drill- ing/routing of printing circuit board materials.
• the present invention further relates to a method of making a cemented carbide body comprising one or more hard constituents and a binder phase based on cobalt, nickel and/or iron by powder metallurgical methods mil- ling, pressing and sintering of powders forming hard constituents and binder phase whereby said binder phase contains 10-30 wt-% Ru.
• At least part of the binderphase powder consists of non agglomerated particles of spheroidal morphology of about 0.4 ⁇ m average grain size and with a narrow grain size distribution wherein at least 80 % of the particles have sizes in the interval x ⁇ O .2x provided that the interval of variation (that is 0.4x) is not smaller than 0.1 ⁇ m.
• the advantages offered by the ruthenium additions are as mentioned a further element of grain growth refinement, an increase in resistance to chemical attack and a strengthening of the binder phase without significantly affecting the edge toughness due to the increase in cobalt content used.
• Cemented carbide PCB-router according to the invention were made with the composition 1.9 % Ru, 5.6 % Cobalt the remainder WC (0.2 ⁇ m grain size), with about 0.7 % (VC + Cr3C2) grain growth inhibitor.
• the material had a hardness of 2080HV and a K1C of 8.75 MPam 1 ⁇ .
• the routers were ground to 2.4 mm dia and tested as follows :
• Test 1 30,000 RPM,1.2 m/min feedrate, 150 m of cut
• Test 2 42,000 RPM,2.2 m/min feedrate, 100 m of cut
• test 1 routers according to the invention reached 150 m of cut with 25% less average wear than the prior art routers which used 6% cobalt.
• 2.4 mm dia routers were made from cemented carbides with varying ruthenium contents as follows:
• Composition 1 1.0%Ru,6.3%Co,0.7VC+Cr 3 C 2 ,0.2 ⁇ m WC Composition 2 1.4%Ru,6.0%Co, 0.7VC+Cr 3 C 2 ,0.2 ⁇ m WC Composition 3 1.9%Ru,5.6%Co, 0.7VC+Cr 3 C 2 , 0.2 ⁇ m WC
• the routers were tested as follows:
• Cemented carbide PCB microdrills according to the invention were made with the composition 2.2 % Ru, 6.4 % Co the remainder WC (0.4 ⁇ m grain size), with about 0.8 % (VC + Cr3C2) grain growth inhibitor.
• the material had a hardness of 2010HV and a K1C of 8 MPam 1 ⁇ .
• microdrills were tested and the wear measured. It was found that the prior art materials exhibited 10- 15 % less wear resistance and 10-15 % less resistance to breakage during an increasing feed rate that started at 15 ⁇ m/rev and increasing towards 70.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Cutting Tools, Boring Holders, And Turrets (AREA)
• Powder Metallurgy (AREA)
• Drilling Tools (AREA)
• Drilling And Boring (AREA)

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Cited By (19)

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Citations (8)

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• 1997
  • 1997-09-05 SE SE9703204A patent/SE9703204L/ not_active Application Discontinuation
• 1998
  • 1998-09-04 AT AT98943147T patent/ATE254189T1/de not_active IP Right Cessation
  • 1998-09-04 DE DE69819762T patent/DE69819762T2/de not_active Expired - Lifetime
  • 1998-09-04 JP JP2000510904A patent/JP2001515963A/ja active Pending
  • 1998-09-04 EP EP98943147A patent/EP1019559B1/en not_active Expired - Lifetime
  • 1998-09-04 US US09/486,586 patent/US6521172B2/en not_active Expired - Fee Related
  • 1998-09-04 KR KR1020007002317A patent/KR100547534B1/ko not_active Expired - Fee Related
  • 1998-09-04 WO PCT/SE1998/001574 patent/WO1999013121A1/en not_active Ceased
  • 1998-09-04 CN CN98808878A patent/CN1088116C/zh not_active Expired - Fee Related
• 2002
  • 2002-10-23 US US10/278,073 patent/US6830604B2/en not_active Expired - Fee Related

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