Casting size and shape determines the tolerance required to allow for process variables. These allowances will vary by foundry, depending on foundry experience or process control capabilities.
Many process factors affect investment-casting tolerances, including:

1. Wax Temperature          
2. Firing Temperature
3. Type of Wax              
4. Pouring Temperature
5. Pressure of Wax Injection   
6. Rate of Cool
7. Design Configuration
8. Mold or Shell Backup Sand Composition  
9. Number of Coats Applied

Standard linear tolerances

As a general rule...normal linear tolerances on an investment casting can be +. 010" for up to 1", and +. 005" for each additional inch thereafter.
Normal tolerances can be expected for production repeatability of all casting dimensions.

Premium tolerances require additional operations at extra cost and achieve closer tolerances on selected dimensions only, even tighter tolerance than those on the following chart can be obtained

General casting tolerance

Dimensions (mm)		Precision Grade
		Normal		Premium
From	To	Deviation + or --	Tolerance Range	Deviation + or --	Tolerance Range
0	6	± 0,10	0.20	± 0,08	0.16
6	10	± 0,12	0.24	± 0,10	0.20
10	14	± 0,15	0.30	± 0,12	0.24
14	18	± 0,20	0.40	± 0,14	0.28
18	24	± 0,25	0.50	± 0,17	0.34
24	30	± 0,30	0.60	± 0,20	0.40
30	40	± 0,36	0.72	± 0,25	0.50
40	50	± 0,42	0.84	± 0,30	0.60
50	65	± 0,49	0.98	± 0,35	0.70
65	80	± 0,58	1.16	± 0,42	0.84
80	100	± 0,68	1.36	± 0,48	0.96

Flatness

Degree of flatness in an investment casting is almost always determined by the volumetric shrinkage of wax and metal during cooling. Usually in the center of the mass, this shrinkage is called "dish" (shrinkage, dip, or "out of flat"). Dish can be controlled by specialized techniques, but it will always occur to some extent. General flatness tolerances cannot be quoted because they vary with configuration and alloy used. The following is a rough guide for areas under 6 square inches.

Rough guide for Flatness tolerance is ± 0,25 up to 100 sq. mm of surface area.

Straightness

Straightness may be a real problem with certain types of castings. A relatively thin, short part may bend while a long, heavy part may not. Experience tells the foundry a given design may bend, but experience cannot indicate to what extent. As a rough guide, a constant section will usually have an axial bow of .005" per inch. Ribs and gussets will inhibit warpage, but also hinder mechanical straightening of whatever warpage occurs.

Process Capabilities:

Minimum and maximum weight limitations from 0.2g to 90Kg
Minimum and maximum size limitations.100mm – 1000mm
Cast surface roughness for example Carbon steel Ra6.4~12.5