VDG P690: Lamháltais réitigh chaighdeánacha idirnáisiúnta

In the manufacturing world, precision is key, especially in casting.

Dimensional accuracy can make or break a component’s functionality, which is why tolerance standards are so important.

Ina measc seo, the VDG P690 standard is widely recognized for defining linear dimension tolerances in cast parts.

Sa bhlag seo, we’ll dive into the details of VDG P690, its key aspects, how it compares to other tolerance standards, and why it is a cornerstone for quality control in casting.

1. Introduction to VDG P690

VDG P690 is a standard developed by the Association of German Foundry Experts (Verband Deutscher Giessereifachleute, VDG) that specifies linear dimensional tolerances for castings.

As casting processes can naturally lead to variations in part dimensions due to material behavior and production conditions, VDG P690 ensures that these deviations remain within acceptable limits.

This standard is used to maintain dimensional consistency, improve part reliability, and minimize potential issues during assembly.

Manufacturers across various industries rely on VDG P690 to guarantee the dimensional accuracy of cast parts, ensuring that they meet both functional and safety requirements.

Whether the application involves complex machinery, Comhpháirteanna na ngluaisteán, or large-scale industrial equipment, VDG P690 provides clear and detailed guidance.

2. Why Tolerances Are Important

Tolerances are critical in any manufacturing process because they define the allowable limits of deviation from the intended dimensions of a part.

In casting, where parts are often subject to shrinkage, thermal expansion, and other variables, dimensional tolerances help ensure that parts fit together correctly and perform their intended function.

Maintaining strict tolerances ensures that:

• Parts fit together correctly.
• Components function as intended.
• Quality and reliability are consistent across production batches.
• Scrap and rework are minimized, leading to cost savings.
• Customer satisfaction is maintained through reliable and high-quality products.

3. Dimensional Tolerances of VDG P690

The VDG P690 standard is structured around tolerance classes that correspond to different levels of dimensional precision.

Understanding the various aspects of this standard is crucial for both manufacturers and designers.

3.1 Linear tolerances

The dimensional tolerances achievable on investment castings are dependent on the following factors:

> casting material

> casting dimensions and shape

In production, the tolerance range of dispersion is affected by the varying characteristics of the materials.
For this reason, different tolerance series apply for different groups of casting materials:

• Grúpa Ábhar D.: cóimhiotail bunaithe ar iarann-nicil, cóbalt, agus Cooper
  Grád cruinnis: D1 go D3
• Material-group A: alloys based on aluminum and magnesium
  Grád cruinnis: A1 to A3
• Material-group T: alloys based on titanium
  Grád cruinnis: T1 to T3

Three accuracy grades are stated for each of the material groups D, A, and T.

• Grád cruinnis 1 applies for all free-sized dimensions.
• Grád cruinnis 2 applies for all dimensions to be toleranced.
• Grád cruinnis 3 can only be met for certain dimensions and must be agreed upon with the casting manufacturer, as additional production processes and costly tooling adjustments are necessary.

Lamháltais réitigh líneach tríthoiseach (DCT i MM) le haghaidh gráid lamháltais réitigh tríthoiseacha (Dctg) Grúpa Ábhar D.

	Nominal dimension range	D1		D2		D3
		DCT	Dctg	DCT	Dctg	DCT	Dctg
	suas go dtí 6	0,3	5	0,24	4	0,2	4
	i gcaitheamh 6 up go dtí 10	0,36		0,28	5	0,22
	i gcaitheamh 10 up go dtí 18	0,44	6	0,34		0,28
	i gcaitheamh 18 up go dtí 30	0,52		0,4		0,34	5
	i gcaitheamh 30 up go dtí 50	0,8	7	0,62	6	0,5
	i gcaitheamh 50 up go dtí 80	0,9		0,74		0,6	6
	i gcaitheamh 80 up go dtí 120	1,1		0,88		0,7
	i gcaitheamh 120 up go dtí 180	1,6	8	1,3	7	1,0
	i gcaitheamh 180 up go dtí 250	2,4	9	1,9	8	1,5	8
	i gcaitheamh 250 up go dtí 315	2,6		2,2		1,6	7
	i gcaitheamh 315 up go dtí 400	3,6	10	2,8	9
	i gcaitheamh 400 up go dtí 500	4,0		3,2
	i gcaitheamh 500 up go dtí 630	5,4	11	4,4	10
	i gcaitheamh 630 up go dtí 800	6,2		5,0
	i gcaitheamh 800 up go dtí 1000	7,2
	i gcaitheamh 1000 up go dtí 1250

Lamháltais réitigh líneach tríthoiseach (DCT i MM) le haghaidh gráid lamháltais réitigh tríthoiseacha (Dctg) material group A

Nominal dimension range	A1		A2		A3
	DCT	Dctg	DCT	Dctg	DCT	Dctg
suas go dtí 6	0,3	5	0,24	4	0,2	4
i gcaitheamh 6 up go dtí 10	0,36		0,28	5	0,22
i gcaitheamh 10 up go dtí 18	0,44	6	0,34		0,28
i gcaitheamh 18 up go dtí 30	0,52		0,4		0,34	5
i gcaitheamh 30 up go dtí 50	0,8	7	0,62	6	0,5
i gcaitheamh 50 up go dtí 80	0,9		0,74		0,6	6
i gcaitheamh 80 up go dtí 120	1,1		0,88		0,7
i gcaitheamh 120 up go dtí 180	1,6	8	1,3	7	1,0
i gcaitheamh 180 up go dtí 250	1,9		1,5	8	1,2	7
i gcaitheamh 250 up go dtí 315	2,6	9	2,2		1,6
i gcaitheamh 315 up go dtí 400	2,8		2,4	9	1,7	8
i gcaitheamh 400 up go dtí 500	3,2		2,6	8	1,9
i gcaitheamh 500 up go dtí 630	4,4	10	3,4	9
i gcaitheamh 630 up go dtí 800	5,0		4,0
i gcaitheamh 800 up go dtí 1000	5,6		4,6	10
i gcaitheamh 1000 up go dtí 1250	6,6

Lamháltais réitigh líneach tríthoiseach (DCT i MM) le haghaidh gráid lamháltais réitigh tríthoiseacha (Dctg) material group T

Nominal dimension range	T1		T2		T3
	DCT	Dctg	DCT	Dctg	DCT	Dctg
suas go dtí 6	0,5	6	0,4	6	0,4	6
i gcaitheamh 6 up go dtí 10	0,6	7	0,4		0,4
i gcaitheamh 10 up go dtí 18	0,7		0,5		0,44
i gcaitheamh 18 up go dtí 30	0,8		0,7	7	0,52
i gcaitheamh 30 up go dtí 50	1,0		0,8		0,62
i gcaitheamh 50 up go dtí 80	1,5	8	1,2	8	0,9	7
i gcaitheamh 80 up go dtí 120	1,7		1,4		1,1
i gcaitheamh 120 up go dtí 180	2,0		1,6		1,3
i gcaitheamh 180 up go dtí 250	2,4	9	1,9		1,5	8
i gcaitheamh 250 up go dtí 315	3,2		2,6	9
i gcaitheamh 315 up go dtí 400	3,6	10	2,8
i gcaitheamh 400 up go dtí 500	4,0		3,2
i gcaitheamh 500 up go dtí 630	5,4	11	4,4	10
i gcaitheamh 630 up go dtí 800	6,2		5,0
i gcaitheamh 800 up go dtí 1000	7,2
i gcaitheamh 1000 up go dtí 1250

3.2 Angle tolerances for material groups D, A, and T

Nominal dimension range 1)	Cruinneas3)
	1		2		3
	Allowed deviation de treo
	Angular minute	mm per 100 mm	Angular minute	mm per 100 mm	Angular minute	mm per 100 mm
up go dtí 30 mm	30 2)	0,87	30 2)	0,87	20 2)	0,58
i gcaitheamh 30 up go dtí 100 mm	30 2)	0,87	20 2)	0,58	15 2)	0,44
i gcaitheamh 100 up go dtí 200 mm	30 2)	0,87	15 2)	0,44	10 2)	0,29
i gcaitheamh 200 mm	30 2)	0,58	15 2)	0,44	10 2)	0,29

Cuir ar an méar fhada 2: Angle tolerances

Tolerances deviating from Table 2 must be agreed on between supplier and user and entered in the drawing following DIN ISO 1101.

3.3 Radius of curvature

The tolerances stated apply to the material groups D, A, and T

Nominal dimension range	Cruinneas1)
	1	2	3
	The radius of curvature [mm]
up go dtí 5 mm	± 0,30	± 0,20	± 0,15
i gcaitheamh 5 up go dtí 10 mm	± 0,45	± 0,35	± 0,25
i gcaitheamh 10 up go dtí 120 mm	± 0,70	± 0,50	± 0,40
i gcaitheamh 120 mm	linear (cf. table 1)

Cuir ar an méar fhada 3: Radius of curvature for material groups D, A and T

Radii of curvature deviating from Table 3 must be agreed on with the investment casting foundry.

3.4 Surface quality

For cast surfaces, Eas (CLA) shall be applied following table

Tar chun tosaigh caighdeáin	Ábhar group D		Ábhar group A		Ábhar group T
	CLA [µinch]	Ra [µm]	CLA [µinch]	Ra [µm]	CLA [µinch]	Ra [µm]
Thuaidh 7	63	1,6
Thuaidh 8	125	3,2	125	3,2
Thuaidh 9	250	6,3	250	6,3	250	6,3

Zone N7, N8, and special surface treatment must be agreed separately and entered in the drawing following DIN ISO 1302.
Unless otherwise agreed, N9 in the shot-blasted state is the standard delivery condition.

4. Factors Affecting Dimensional Tolerances

Several factors influence the dimensional tolerances of cast parts, making it important to understand these variables when applying VDG P690 standards:

• Airíonna Ábhartha: Different materials react differently during the casting process.
  Mar shampla, aluminum and steel may experience different rates of shrinkage or warping as they cool, which can affect the final dimensions.
• Modh réitigh: The choice of casting method—whether sand casting, réitigh bás, or investment casting—can also impact the achievable tolerances.
  Die casting, mar shampla, generally allows for tighter tolerances than sand casting due to the more controlled nature of the process.
• Cuid Castacht: More intricate designs or parts with complex geometries are more prone to dimensional deviations.
  Parts with thin walls, small features, or intricate shapes may require more precise control over tolerances to ensure accuracy.

5. How VDG P690 Improves Quality Control

The VDG P690 standard plays a critical role in enhancing quality control in casting operations. Clearly defining tolerance limits.

Helps manufacturers maintain consistent product quality across batches and production runs. This leads to several key benefits:

• Dramhaíl laghdaithe: By ensuring that parts meet tolerance requirements, manufacturers minimize the number of rejected or scrapped parts, reducing waste and costs.
• Improved Assembly: Properly toleranced parts fit together more easily, reducing the likelihood of assembly errors and ensuring that products work as intended.
• Enhanced Customer Satisfaction: Consistency in casting dimensions leads to fewer customer complaints and warranty claims, improving overall satisfaction and building long-term trust with clients.

6. VDG P690 vs. Other Tolerance Standards

VDG P690 is one of several tolerance standards used in the casting industry. How does it compare to other standards, such as ISO 8062 or ASTM A956?

• VDG P690: This standard is particularly known for its detailed classification of tolerances across different part sizes and tolerance classes,
  offering more granular control over precision than some other standards.
• Iso 8062: Iso 8062 is a more globally recognized standard for casting tolerances and covers a broad range of materials and casting processes.
  Cén dóigh faoin spéir a ...?, it is often viewed as less specific in certain cases compared to VDG P690.
• ASTM A956: Primarily used in the United States, ASTM standards provide guidelines for specific casting materials.
  ASTM A956, mar shampla, focuses on the hardness of cast parts rather than linear dimensional tolerances, making it complementary to standards like VDG P690.

7. Deireadh

VDG P690 stands as a vital tool for ensuring the precision and reliability of cast components.

Its comprehensive classification of tolerance classes and flexibility in addressing different part sizes and complexities make it an indispensable standard for manufacturers.

By adhering to the VDG P690 standard, manufacturers can achieve better product performance, reduce waste, and enhance customer satisfaction.

If you’re involved in casting or using cast parts in your products, understanding and applying VDG P690 is essential for maintaining quality and meeting the demands of modern manufacturing.

Content reference：www.bdguss.de