Production process of in-mold T-core

Abstract

The invention relates to the technical field of inductors, in particular to a production process of an in-mold T-core. Comprising the following steps that a hot-pressing middle mold flows into a T-core forming machine table, an upper mold cover descends to be pressed to the hot-pressing middle mold, and the shape of a mold cavity is adjusted into the shape of the T-core; the mold cavity is filled with iron powder for the first time, the iron powder is extruded through an upper punch and a lower punch, and T-core is formed in the mold cavity; after forming, the hot-pressing middle mold is turned over by 180 degrees, and the front face of a middle column of the T-core faces upwards; winding a coil on a middle column of the T-core by a winding machine, bending a lead downwards by 90 degrees and then fixing the lead to obtain the T-core sleeved with the coil; and the T-core sleeved with the coil is combined with a hot-pressing middle mold and a bottom plate, the T-core is fed into a hot press to be subjected to hot pressing after secondary filling of iron powder, and the T-core formed through hot pressing is obtained. According to the process, the problem of T-core breakage can be solved, the product yield is improved, and the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of inductor technology, and more specifically, to an in-mold T-core manufacturing process. Background Technology

[0002] In the field of electronic component manufacturing, T-cores (T-shaped magnetic cores) are core components of devices such as inductors and transformers, and their manufacturing process directly affects product performance and production costs. Currently, the out-of-mold T-core manufacturing process is widely used, and its specific process is as follows: First, the T-core is formed in a mold. Then, the T-core is removed from the mold, baked in an oven, and the coil is assembled by bending its corners. Next, the assembled coil and the T-core are placed together into a hot press mold, filled with iron powder, and then the final forming is completed by a hot press. However, this process has significant drawbacks: high risk of T-core breakage: because the T-core needs to be removed from the mold and transferred separately to subsequent processes, its structure is fragile and easily affected by mechanical stress during handling and assembly, leading to breakage and reduced product yield; copper leakage defects: when assembling the coil on the T-core after demolding, the bending angle of the copper wire is difficult to control precisely, resulting in poor contact between the coil and the T-core. Uneven iron powder filling during hot pressing also easily leads to copper wire leakage defects on the final product surface; complex process flow and high cost: multiple mold operations and transfer steps are required, resulting in large equipment investment, low production efficiency, and high rework costs for defective products. These problems severely restrict the large-scale production of T-core products. Therefore, an innovative process that can simplify the process flow, improve product yield, and reduce costs is urgently needed.

[0003] Chinese invention patent application CN119943568A discloses a method for preparing a high-conductivity inductor, including the following steps: S1, winding a coil by winding an insulating wire into a hollow shape, with lead ends at both ends of the coil; S2, removing the insulating layer by removing the insulating layer from the lead ends; S3, molding a magnetic core by molding a mixture of magnetic materials around the coil, exposing the lead ends for connecting to external terminals. The method involves winding an insulating wire into a hollow shape, extending the two ends of the coil as lead ends, removing the insulating layer from the lead ends, pre-peeling the varnish film at the coil lead positions, and then hot-pressing. However, this T-core requires removal from the mold and separate transfer to subsequent processes. Its structure is fragile and easily affected by mechanical stress during handling and assembly, leading to breakage and reduced product yield. Summary of the Invention

[0004] This invention provides an in-mold T-core manufacturing process, comprising the following steps:

[0005] The hot-pressing middle mold flows into the T-core molding machine, and the upper mold cover is lowered and pressed into the hot-pressing middle mold, adjusting the shape of the mold cavity to the T-core shape;

[0006] Iron powder is filled into the mold cavity once, and the iron powder is extruded by the upper and lower punches to form a T-core in the mold cavity; after forming, the hot pressing mold is rotated 180° so that the central column of the T-core faces upward.

[0007] The winding machine winds the coil and moves it onto the carrier. The lead wire is cut and bent downwards at 90° using auxiliary accessories. The coil is then removed from the carrier and moved into the hot press mold and placed onto the T-core central column.

[0008] Then, the coil leads are bent using auxiliary accessories, followed by the combination of the middle mold and the middle mold base plate. After filling with iron powder, the coils are sent to a hot press for hot pressing.

[0009] This invention's in-mold T-core manufacturing process completes the T-core molding, coil winding, and fixing all within the mold, avoiding the traditional step of removing the T-core from the mold and transferring it separately to subsequent processes. This significantly reduces the mechanical stress on the T-core during handling and assembly, thereby lowering the risk of T-core breakage and improving product yield. Simultaneously, the in-mold winding and fixing of the coil ensures precise contact between the coil and the T-core, preventing copper wire exposure defects caused by uneven iron powder filling during hot pressing. This further improves product yield.

[0010] The amount of iron powder added at one time is 0.07-0.1g.

[0011] Optionally, the amount of iron powder added at one time is 0.07-0.09g.

[0012] Optionally, the amount of iron powder filled at one time is 0.08g.

[0013] The thickness of the central column of the T-core formed in the mold cavity is 1.2-1.5mm, and the thickness of the plate is 0.5-0.9mm.

[0014] Optionally, the thickness of the central column of the T-core formed in the mold cavity is 1.3-1.35mm, and the thickness of the plate is 0.6-0.8mm.

[0015] Optionally, the thickness of the central pillar of the T-core formed in the mold cavity is 1.3 mm, and the thickness of the plate is 0.7 mm.

[0016] The extrusion temperature is 70-100℃ and the pressure is 0.3-0.8T.

[0017] Optionally, the extrusion temperature is 70-90℃ and the pressure is 0.4-0.7T.

[0018] Optionally, the extrusion temperature is 80°C and the pressure is 0.5T.

[0019] The height of the wound coil is 1.2-1.5mm.

[0020] Optionally, the height of the wound coil is 1.2-1.4 mm.

[0021] Optionally, the height of the wound coil is 1.3 mm.

[0022] The amount of iron powder used for secondary filling is 0.07-0.1g.

[0023] Optionally, the amount of iron powder used for secondary filling is 0.07-0.09g.

[0024] Optionally, the amount of iron powder used for secondary filling is 0.08g.

[0025] The thickness of the hot-pressed T-core is 2.0-2.2 mm.

[0026] Optionally, the thickness of the hot-pressed T-core is 2.0-2.1 mm.

[0027] Optionally, the thickness of the hot-pressed T-core is 2.0 mm.

[0028] The length and width of the hot-pressed T-core are both 3-5mm.

[0029] Optionally, the length and width of the hot-pressed T-core are both 3.8-4.5 mm.

[0030] Optionally, the length and width of the hot-pressed T-core are both 4.19 mm.

[0031] The length and width of the hot-pressed T-core are both 1-2 mm.

[0032] Optionally, the length and width of the hot-pressed T-core are both 1.2-1.6 mm.

[0033] Optionally, the length and width of the hot-pressed T-core are both 1.4 mm.

[0034] The hot pressing temperature is 150-190℃, and the pressure is 0.5-0.8T.

[0035] Optionally, the hot pressing temperature is 160-180℃ and the pressure is 0.6-0.7T.

[0036] Optionally, the hot pressing temperature is 170°C and the pressure is 0.65T.

[0037] The preheating time for hot pressing is 20-50 seconds, and the holding time is 40-70 seconds.

[0038] Optionally, the preheating time for hot pressing is 20-40 seconds, and the holding time is 40-60 seconds.

[0039] Optionally, the preheating time for the hot pressing is 30 seconds, and the pressure holding time is 50 seconds.

[0040] The iron powder includes either iron-silicon-chromium alloy powder or carbonyl iron powder, and the D50 (median particle size) particle size of the iron powder is 4-15 micrometers.

[0041] Optionally, the carbonyl iron powder is purchased from Jiangsu Tianyi Ultrafine Metal Powder Co., Ltd., model: RZE, with a D50 (median particle size) of 4-7 micrometers.

[0042] Beneficial effects

[0043] 1. The in-mold T-core production process of this invention completes the forming of the T-core and the winding and fixing of the coil within the mold, avoiding the problem of T-core breakage in traditional processes.

[0044] 2. By filling iron powder twice and hot pressing, the structural integrity of the T-core is ensured and production efficiency is improved.

[0045] 3. This invention precisely controls process parameters such as the amount of iron powder filling, extrusion temperature and pressure, coil winding height, hot pressing temperature, pressure, preheating time, and holding time, which helps to further improve product stability and consistency and reduce defect rate.

[0046] 4. The in-mold T-core production process of this invention effectively reduces process steps and lowers production costs.

[0047] 5. The in-mold T-core manufacturing process of this invention solves the copper leakage problem of traditional processes. Attached Figure Description

[0048] Figure 1 This is a process flow diagram for step 1 in the embodiment.

[0049] Figure 2 This is a process flow diagram for step 2 in the embodiment.

[0050] Figure 3 This is a process flow diagram for step 2 in the embodiment.

[0051] Figure 4The process flow diagram in the comparative example shows the winding machine winding the coil and placing it on the fixture plate. Figure 5 The process flow diagram in the comparative example: The T-core is placed inside the coil on the fixture plate. Figure 6 The process flow diagram in the comparative example shows that the T-core+ coil is bent four times on the fixture plate by a bending mechanism. Figure 7 The process flow diagram in the comparative example is: T-core coil assembly + iron powder hot pressing molding product. The components are: 1. Hot-pressing middle mold; 2. Iron powder; 3. T-core mold cavity; 4. Upper punch; 5. Upper mold cover; 6. Lower second punch; 7. Lower next punch; 8. T-core; 9. Coil; 10. T-core with coil; 11. T-core after hot pressing; 12. Fixture plate. Detailed Implementation

[0052] Example

[0053] An in-mold T-core manufacturing process comprises the following steps:

[0054] Step 1: As Figure 1 As shown, the hot pressing die 1 is assembled and separated. The hot pressing die flows into the T-core machine. The T-core machine starts to move. First, the upper die cover 5 descends and sticks to the hot pressing die. The upper die cover 5 extends into the cavity of the hot pressing die 1, changing the cavity of the die from the previous square shape to the shape of a T-core. Iron powder 2 is filled into the T-core cavity 3 of the die. The upper punch 4 descends and enters the T-core cavity 3 of the hot pressing die 1. The lower second punch 6 rises and squeezes the iron powder 2 to form a T-core 8 in the die. Then the upper punch 4 rises to the standby position. The lower second punch 6 and the hot pressing die 1 return to the standby position. The upper die cover 5 rises to the standby position. The hot pressing die is pulled out of the T-core machine. Then the hot pressing die 1 is rotated 180°.

[0055] Step 2: As Figure 2 As shown, the winding machine winds coil 9 and moves the coil to the carrier. After the lead wire is cut and bent downwards by 90° using auxiliary accessories, coil 9 (lead wire downwards) is removed from the carrier and moved to the hot pressing die and placed on the T-core center post (coil lead wire and T-core center post are opposite). Then, the coil lead wire is bent (bent into the die cavity) using auxiliary accessories to obtain T-core (length 4.19mm, width 4.19mm) 10 with coil inside.

[0056] Step 3: As Figure 3 As shown, the middle mold 1 and the middle mold base plate are then combined, and iron powder 2 is filled in a second time before being pressed into a hot press to obtain the hot-pressed T-core 11.

[0057] The amount of iron powder added in one pass is 0.08g.

[0058] The thickness of the central column of the T-core formed in the mold cavity is 1.3 mm, and the thickness of the plate is 0.7 mm.

[0059] The extrusion temperature is 80℃ and the pressure is 0.5T.

[0060] The height of the wound coil is 1.3 mm.

[0061] The amount of iron powder used for secondary filling is 0.08g.

[0062] The thickness of the hot-pressed T-core is 2.0 mm.

[0063] The length and width of the hot-pressed T-core are both 1.4 mm.

[0064] The hot pressing temperature is 170℃ and the pressure is 0.65T.

[0065] The preheating time for the hot pressing is 30 seconds. The holding time is 50 seconds.

[0066] The carbonyl iron powder was purchased from Jiangsu Tianyi Ultrafine Metal Powder Co., Ltd., model: RZE, with a D50 (median particle size) of 4-7 micrometers.

[0067] Comparative Example 1

[0068] A T-core manufacturing process includes the following steps: a winding machine winds a coil, which is then placed on fixture plate 12. Figure 4 ); The T-core is placed inside the coil on the jig plate ( Figure 5 The T-core+ coil is bent four times on the fixture plate by a bending mechanism. Figure 6 T-core coil assembly + iron powder hot pressing molding product ( Figure 7 The hot pressing parameters are the same as in the example.

Claims

1. A process for the production of an in-mold T-core, characterized in that, The method comprises the following steps: The hot-pressing middle mold flows into a T-core forming machine, and the shape of the mold cavity is adjusted to the shape of the T-core by lowering the upper mold cover to press the hot-pressing middle mold; the mold cavity is filled with iron powder once, the iron powder is extruded by the upper punch and the lower punch, and the T-core is formed in the mold cavity; after the forming, the hot-pressing middle mold is turned over by 180°, so that the middle column of the T-core faces upward; the coil is wound by the winding machine, and the coil is moved to the carrier, the lead is cut and bent downward by 90° through the auxiliary accessory, then the coil is separated from the carrier and moved to the hot-pressing middle mold to be sleeved on the middle column of the T-core, then the lead of the coil is bent through the auxiliary accessory, then the middle mold and the middle mold bottom plate are combined, and then the iron powder is filled and sent into the hot press for hot pressing.

2. The process for producing an in-mold T-core according to claim 1, wherein The amount of the iron powder filled once is 0.07-0.1 g.

3. The process for producing an in-mold T-core according to claim 2, wherein The thickness of the middle column of the T-core formed in the mold cavity is 1.2-1.5 mm, and the plate thickness is 0.5-0.9 mm.

4. The process for producing an in-mold T-core according to claim 3, wherein The extrusion temperature is 70-100℃, and the pressure is 0.3-0.8T.

5. The process for producing an in-mold T-core according to claim 1 or 4, wherein The height of the wound coil is 1.2-1.5 mm.

6. The process for producing an in-mold T-core according to claim 1, wherein The amount of the iron powder filled twice is 0.07-0.1 g.

7. The process for producing an in-mold T-core according to claim 6, wherein The thickness of the hot-pressing T-core is 2.0-2.2 mm.

8. The process for producing an in-mold T-core according to claim 7, wherein The length and width of the hot-pressing T-core are both 1-2 mm.

9. The process for producing an in-mold T-core according to claim 1, wherein The hot-pressing temperature is 150-190℃, and the pressure is 0.5-0.8T.

10. The process for producing an in-mold T-core according to claim 9, wherein The preheating time of the hot pressing is 20-50 s, and the pressure maintaining time is 40-70 s.

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