CN107255582A - A kind of sheet-metal press working surface damage Fast simulation experimental provision - Google Patents
A kind of sheet-metal press working surface damage Fast simulation experimental provision Download PDFInfo
- Publication number
- CN107255582A CN107255582A CN201610876374.9A CN201610876374A CN107255582A CN 107255582 A CN107255582 A CN 107255582A CN 201610876374 A CN201610876374 A CN 201610876374A CN 107255582 A CN107255582 A CN 107255582A
- Authority
- CN
- China
- Prior art keywords
- plate
- experimental provision
- support
- sheet
- gear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000006378 damage Effects 0.000 title claims abstract description 23
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 21
- 239000002184 metal Substances 0.000 title claims abstract description 21
- 238000004088 simulation Methods 0.000 title claims abstract description 14
- 230000005540 biological transmission Effects 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 6
- 230000007547 defect Effects 0.000 abstract description 5
- 238000005516 engineering process Methods 0.000 abstract description 5
- 238000011156 evaluation Methods 0.000 abstract description 3
- 238000012360 testing method Methods 0.000 description 9
- 238000005457 optimization Methods 0.000 description 7
- 238000002474 experimental method Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 229910001060 Gray iron Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/286—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q involving mechanical work, e.g. chopping, disintegrating, compacting, homogenising
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C51/00—Measuring, gauging, indicating, counting, or marking devices specially adapted for use in the production or manipulation of material in accordance with subclasses B21B - B21F
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/20—Metals
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a kind of sheet-metal press working surface damage Fast simulation experimental provision, the experimental provision is made up of lower bottom base, upper bed-plate, support, rack, gear and pressure head, wherein lower bottom base is fixedly connected with upper bed-plate, support is made up of support cylinder, driven gear and transverse slat, driven gear is connected with lower bottom base, by support transverse slat is fixed, lower section is meshed with gear above rack, pressure head for it is middle by spring connect it is columnar structured, pressure head one end is fixedly connected with rack.The present invention can be under the conditions of the different Sheet Metal Forming Technology of rapid and convenient simulation plate plucking phenomenon and the qualitative evaluation to galling defect, precision and intelligent height, it is easy to operate, dramatically save manpower and materials.
Description
Technical field
The present invention relates to metal sheet stamping shaping and detection field, and in particular to a kind of sheet-metal press working surface damage is quick
Analogue experiment installation.
Background technology
With flourishing for automobile industry, requirement to automobile also more and more higher will be not only met in security performance
The guarantee in face, while also to embody energy-conserving and environment-protective this theories.Lighter automobile is to realize that the most easy of energy-conserving and environment-protective is also most
An effective approach.Wherein it is one of important means of automotive light weight technology using high intensity thin plate, its high intensity improves vapour
Dent resistance, endurance and the large deformation impact strength of car, it is ensured that security performance, moreover it is possible to effectively mitigate vehicle weight so as to
Reach the purpose of low-fuel-comsuption.And before being manufactured to plate, punching can effectively be evaded to the test of sheet-metal press working surface damage
Press the influence caused to plate, the unnecessary loss produced by reduction production.
During sheet metal forming, when plate is in sliding motion state, due to the pressure between plate and mould
Adhesive wear may occur for contact, and at this moment drip molding surface can be referred to as surface damage by major injury, be commonly called as galling defect,
Plucking generally entails plate transfer or Plastic Flow.But the mode of texturing of the contact, plate between mould and plate and should
Stress-strain state etc. is all continually changing, and the contact conditions of mould and plate also constantly deteriorate, such as Contact Temperature rise, coefficient of friction
Increase etc., so that the risk factor of surface damage phenomenon is numerous.
Simulated automotive panel surface galling defect method --- Lin Zhong admires(Patent publication No.:CN1818606A), should
Patent simulates the surface damage phenomenon in Sheet Metal Stamping Process using the cell type part drawing of the radius of corner such as not, and mould structure is multiple
Miscellaneous, manufacturing expense is high, and needs to carry out Pressing Deformation compared with great tonnage press;Surface damage phenomenon in other punching course is mould
The accumulation results of mutual sliding friction between tool-plate, therefore the patented technology also needs to expend substantial amounts of plate and carries out cell type part
Shock pressure experiments, it is also desirable to plenty of time and manpower, causes the waste of great manpower and materials, and because galling defect is scattered,
Cause to evaluate difficult.
The content of the invention
The purpose of the present invention is that there is provided a kind of sheet-metal press working surface damage Fast Modular for above-mentioned deficiency of the prior art
Draft experiment device.
The technical scheme is that:A kind of sheet-metal press working surface damage Fast simulation experimental provision, it is characterised in that:Institute
State experimental provision to be made up of lower bottom base, upper bed-plate, support, rack, gear and pressure head, the lower bottom base is fixed with upper bed-plate to be connected
Connect;The upper bed-plate is " recessed " shape structure, and the upper bed-plate is provided with a circular hole;The support is by support cylinder, driven
Gear and transverse slat composition, described support cylinder one end be connected with driven gear, the other end and transverse slat connection, the driven gear and
Lower bottom base is connected, and the support cylinder passes through the upper bed-plate circular hole;Fixed above the rack by support transverse slat, lower section and tooth
Wheel is meshed, and the gear is two, is separately positioned on transverse slat both sides, and the pressure head is the middle cylindrical shape knot connected by spring
Structure, described pressure head one end is fixedly connected with the rack.
Optimization;The lower bottom base is bolted to connection with upper bed-plate.
Optimization;The lower bottom base is provided with groove, the groove is provided with driving gear provided with motor I, groove top,
The driving gear is driven by the motor I, and the driving gear is meshed with driven gear.
Optimization;The support transverse slat both sides are provided with convex portion, are equipped with motor II in the convex portion, the convex portion respectively with
The gear is corresponding, and the gear is respectively by being arranged on the transmission of motor II of transverse slat convex portion.
Optimization;The lower bottom base is provided with fixed cylinder, and the center of described support driven gear one end is provided with and institute
The hole slot that fixed cylinder matches is stated, the fixed cylinder is inserted to be flexibly connected in the hole slot with the support.
Optimization;The upper bed-plate both sides are respectively equipped with portrait, and the portrait center is provided with screw and nut, the portrait
Inner side is provided with plate fixed plate, and the plate fixed plate center is provided with blind hole, and the nut is through the screw and inserts described
In blind hole.
Optimization;It is carved with scale in the upper bed-plate upper surface.
Optimization;The rack is provided with nut bore, and one end that the pressure head is connected with rack is provided with nut head, the spiral shell
Female is connected with the nut bore.
Advantages of the present invention:The experimental provision of the present invention can quickly and easily simulate the surface in plate stamping process
Damage phenomenon and the qualitative evaluation to galling defect, precision and intelligent height, it is easy to operate, dramatically save people
Power material resources.
Brief description of the drawings
Fig. 1 is front view of the invention;
Fig. 2 is left view of the invention;
Fig. 3 is rearview of the invention;
Fig. 4 is support front view;
Fig. 5 is support right view;
Fig. 6 is upper bed-plate top view;
Fig. 7 is lower bottom base front view;
Fig. 8 is lower bottom base main sectional view;
Fig. 9 is lower bottom base top view;
Figure 10 is plate fixed plate front view;
Figure 11 is plate fixed plate right sectional view;
The enlarged drawing that Figure 12 is A in Figure 11.
Embodiment
With specific embodiment, the present invention is further described below.
Embodiment:
As shown in Figures 1 to 12, a kind of sheet-metal press working surface damage Fast simulation experimental provision, described device by lower bottom base 1, on
Base 2, support 3, rack 4, gear 5 and pressure head 6 are constituted, and the lower bottom base 1 is manufactured by Steel material, and upper bed-plate 2 is by aluminium alloy material
Material manufacture, support 3 is manufactured by gray cast iron material, and rack 4 is manufactured by aluminum alloy materials, and pressure head 6 is manufactured by aluminum, the bottom
Seat 1 is fixedly connected with upper bed-plate 2 by bolt 11, and the lower bottom base 1 is provided with groove 12 and fixed cylinder 13, the groove 12
Interior to be provided with driving gear 14 provided with motor I, the top of groove 12, the driving gear 14 is driven by the motor I;The upper bed-plate
2 be " recessed " shape structure, and the upper bed-plate 2 is respectively equipped with portrait 22, the center of portrait 22 provided with circular hole 21, a both sides
Provided with screw and nut 24, the inner side of portrait 22 is provided with plate fixed plate 23, and the center of plate fixed plate 23 is provided with blind hole
25, the nut 24 is through the screw and inserts in the blind hole 25, and scale is carved with the upper bed-plate upper surface;The support
3 are made up of support cylinder 33, driven gear 34 and transverse slat 35, it is described support the one end of cylinder 33 be connected with driven gear 34, it is another
End is connected with transverse slat 35, and the center of described one end of driven gear 34 is provided with the hole slot matched with the fixed cylinder 13, institute
State fixed cylinder 13 and insert in the hole slot and be flexibly connected with the support 3, the driving gear 14 is mutually nibbled with driven gear 34
Close, the both sides of transverse slat 35, which are provided with convex portion 36, the convex portion 36, is equipped with motor II, the support cylinder 33 passes through the circle
Hole 21;The top of rack 4 is fixed by transverse slat 35, lower section is meshed with gear 5, and the rack 4 is provided with nut bore, the tooth
Wheel 5 is two, is separately positioned on the both sides of transverse slat 35 and corresponding with the convex portion 36, the gear 5 is respectively by being arranged on convex portion
36 motor II is driven;The pressure head 6 for it is middle by spring 61 connect it is columnar structured, described one end of pressure head 6 is provided with nut
First 62, the nut head 62 is connected with the nut bore.
During experiment, test plate is placed on upper bed-plate, tightening or unscrew come the plate that promotes or retract by nut 24
Plate fixed plate 23 is fixed on upper bed-plate by fixed plate 23 so as to fixed test plate according to the scale on upper bed-plate upper surface
Center.The motor I in the groove 12 of lower bottom base 1 is opened, makes it drive driving gear 14 to rotate, passes through driving gear 14 and driven tooth
The transmission of wheel 34, drives support 3 to rotate, so as to be moved in a circle with dynamic head 7 on test plate, while it is convex to open transverse slat 35
The motor II in portion 36, rotates its band moving gear 5, so as to be moved along a straight line with dynamic head 7 on test plate.Due to pressure head 7
Centre is connected by spring, and the coefficient of elasticity of spring is fixed, and the pressure of 7 pairs of test plates of pressure head makes spring-compressed, so as to obtain bullet
The stroke of spring, the coefficient of elasticity further according to spring draws the power that spring is produced, so as to reach control pressure head to test sheet feeding table
The effect of surface pressure.Motor I and motor II are clockwise and anticlockwise motor, with reference to different rotating speeds, can be produced on test plate
A variety of different scratch patterns, therefore different strokes left by different pressures different rotating speeds push-down head 7 on test plate
Trace pattern can simulate influence of the different Sheet Metal Forming Technology conditions to panel surface quality, and can be according to the order of severity of cut to table
Surface damage carries out qualitative evaluation.
Claims (8)
1. a kind of sheet-metal press working surface damage Fast simulation experimental provision, it is characterised in that:The experimental provision by lower bottom base, on
Base, support, rack, gear and pressure head composition, the lower bottom base are fixedly connected with upper bed-plate;The upper bed-plate is " recessed " shape
Structure, the upper bed-plate is provided with a circular hole;The support is made up of support cylinder, driven gear and transverse slat, the support
Cylinder one end is connected with driven gear, the other end and transverse slat are connected, and the driven gear is connected with lower bottom base, the support cylinder
Through the upper bed-plate circular hole;By support transverse slat is fixed, lower section is meshed with gear above the rack, the gear is two
It is individual, be separately positioned on transverse slat both sides, the pressure head for it is middle by spring connect it is columnar structured, described pressure head one end with it is described
Rack is fixedly connected.
2. a kind of sheet-metal press working surface damage Fast simulation experimental provision according to claim 1, it is characterised in that:It is described
Lower bottom base is bolted to connection with upper bed-plate.
3. a kind of sheet-metal press working surface damage Fast simulation experimental provision according to claim 1, it is characterised in that:It is described
Lower bottom base is provided with groove, the groove provided with driving gear is provided with above motor I, groove, and the driving gear is by described
Motor I is driven, and the driving gear is meshed with driven gear.
4. a kind of sheet-metal press working surface damage Fast simulation experimental provision according to claim 3, it is characterised in that:It is described
Support transverse slat both sides are provided with convex portion, the convex portion and are equipped with motor II, and the convex portion is corresponding with the gear respectively, described
Gear is respectively by being arranged on the transmission of motor II of transverse slat convex portion.
5. a kind of sheet-metal press working surface damage Fast simulation experimental provision according to claim 3 or 4, it is characterised in that:
The lower bottom base is provided with fixed cylinder, and the center of described support driven gear one end is provided with to match with the fixed cylinder
Hole slot, the fixed cylinder is inserted to be flexibly connected in the hole slot with the support.
6. a kind of sheet-metal press working surface damage Fast simulation experimental provision according to claim 1, it is characterised in that:It is described
Upper bed-plate both sides are respectively equipped with portrait, and the portrait center is provided with the inside of screw and nut, the portrait and is provided with plate fixed plate,
The plate fixed plate center is provided with blind hole, and the nut is through the screw and inserts in the blind hole.
7. a kind of sheet-metal press working surface damage Fast simulation experimental provision according to claim 6, it is characterised in that:It is described
It is carved with scale in upper bed-plate upper surface.
8. a kind of sheet-metal press working surface damage Fast simulation experimental provision according to claim 1, it is characterised in that:It is described
Rack is provided with nut bore, and one end that the pressure head is connected with rack is provided with nut head, and the nut head connects with the nut bore
Connect.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201610876374.9A CN107255582B (en) | 2016-10-08 | 2016-10-08 | Rapid simulation experiment device for sheet stamping surface damage |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201610876374.9A CN107255582B (en) | 2016-10-08 | 2016-10-08 | Rapid simulation experiment device for sheet stamping surface damage |
Publications (2)
Publication Number | Publication Date |
---|---|
CN107255582A true CN107255582A (en) | 2017-10-17 |
CN107255582B CN107255582B (en) | 2020-05-12 |
Family
ID=60027830
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201610876374.9A Expired - Fee Related CN107255582B (en) | 2016-10-08 | 2016-10-08 | Rapid simulation experiment device for sheet stamping surface damage |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN107255582B (en) |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1818606A (en) * | 2006-01-12 | 2006-08-16 | 上海交通大学 | Method for simulating defection of surface coarsing of automotive plates |
CN2907943Y (en) * | 2006-05-26 | 2007-06-06 | 宝山钢铁股份有限公司 | Plate material rough quantity measuring device for automobile body |
CN101266201A (en) * | 2008-04-21 | 2008-09-17 | 上海大学 | Metal sheet friction coupling deformation testing device |
CN102323167A (en) * | 2011-08-16 | 2012-01-18 | 上海交通大学 | Sheet stamping surface damage test apparatus for realizing a plurality of deformation states |
CN203117062U (en) * | 2013-01-16 | 2013-08-07 | 南京理工大学 | Multi-station multi-direction movement abrasion tester |
CN103278412A (en) * | 2013-05-23 | 2013-09-04 | 浙江工业大学 | Low-load friction-wear test device |
CN103822837A (en) * | 2014-02-07 | 2014-05-28 | 河南科技大学 | Friction testing machine |
CN103913392A (en) * | 2014-04-04 | 2014-07-09 | 浙江大学 | Multifunctional wear test device for material wear analysis |
CN104089840A (en) * | 2014-06-10 | 2014-10-08 | 华晨汽车集团控股有限公司 | Testing device for friction wear property of automobile stamping die material |
CN105115843A (en) * | 2015-09-18 | 2015-12-02 | 四川出入境检验检疫局检验检疫技术中心 | Simulation test device for surface friction resistance of braided fabric |
CN105987853A (en) * | 2015-01-30 | 2016-10-05 | 宝山钢铁股份有限公司 | Testing method and apparatus for block-on-ring friction and wear performance of roller |
-
2016
- 2016-10-08 CN CN201610876374.9A patent/CN107255582B/en not_active Expired - Fee Related
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1818606A (en) * | 2006-01-12 | 2006-08-16 | 上海交通大学 | Method for simulating defection of surface coarsing of automotive plates |
CN2907943Y (en) * | 2006-05-26 | 2007-06-06 | 宝山钢铁股份有限公司 | Plate material rough quantity measuring device for automobile body |
CN101266201A (en) * | 2008-04-21 | 2008-09-17 | 上海大学 | Metal sheet friction coupling deformation testing device |
CN102323167A (en) * | 2011-08-16 | 2012-01-18 | 上海交通大学 | Sheet stamping surface damage test apparatus for realizing a plurality of deformation states |
CN203117062U (en) * | 2013-01-16 | 2013-08-07 | 南京理工大学 | Multi-station multi-direction movement abrasion tester |
CN103278412A (en) * | 2013-05-23 | 2013-09-04 | 浙江工业大学 | Low-load friction-wear test device |
CN103822837A (en) * | 2014-02-07 | 2014-05-28 | 河南科技大学 | Friction testing machine |
CN103913392A (en) * | 2014-04-04 | 2014-07-09 | 浙江大学 | Multifunctional wear test device for material wear analysis |
CN104089840A (en) * | 2014-06-10 | 2014-10-08 | 华晨汽车集团控股有限公司 | Testing device for friction wear property of automobile stamping die material |
CN105987853A (en) * | 2015-01-30 | 2016-10-05 | 宝山钢铁股份有限公司 | Testing method and apparatus for block-on-ring friction and wear performance of roller |
CN105115843A (en) * | 2015-09-18 | 2015-12-02 | 四川出入境检验检疫局检验检疫技术中心 | Simulation test device for surface friction resistance of braided fabric |
Also Published As
Publication number | Publication date |
---|---|
CN107255582B (en) | 2020-05-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN203778608U (en) | V-shaped movable pendulum block bending die and punch press | |
CN101633021B (en) | Hooping cold bending punch forming module | |
CN201088992Y (en) | Double-bending combination die | |
CN206455088U (en) | A kind of hardware sheet stamping staking punch cooling more changing device | |
CN1818606B (en) | Method for simulating defection of surface coarsing of automotive plates | |
CN107626824A (en) | A kind of Production of Stamping Die technique suitable for small-sized aluminium plate | |
CN206825978U (en) | Punching machine skid composite guide rail device | |
CN107255582A (en) | A kind of sheet-metal press working surface damage Fast simulation experimental provision | |
CN106217863A (en) | A kind of copper rivet bearing flexible riveting tool and technique | |
CN206122374U (en) | Floating plug extrusion die structure of ring gear | |
CN219401958U (en) | Stamping die convenient for replacing stamping die head | |
CN106031969A (en) | Processing technology for eccentric body of three-in-one connecting piece | |
CN210547198U (en) | Anti-fracturing bending device for air conditioner parts | |
CN109676051B (en) | Turning device is used in aluminum plate processing | |
CN106623645A (en) | Stamping head cooling replacement device for hardware sheet stamping | |
CN105312383A (en) | Operation method of composite die | |
CN108481412B (en) | Gas transmission receiving device for die-cutting machine | |
CN2743058Y (en) | Vibrating swinging rolling device | |
CN206046686U (en) | A kind of equal channel angular extrusion die of optimization | |
CN205650692U (en) | Bumper shock absorber reinforcing plate bending mould | |
CN1817503A (en) | Precisioning forging method of crawler belt plate | |
CN1530569A (en) | Machining method for symmetrical stepped gear shaft | |
CN206997538U (en) | A kind of Bending Mould for bender | |
CN205763310U (en) | Straight mould is turned round in a kind of Vehicular hinge bending | |
CN205732766U (en) | A kind of double cog blank mould |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant | ||
CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200512 |
|
CF01 | Termination of patent right due to non-payment of annual fee |