SPRUE ,SPECIFICATION,FUNCTION- short notes

-

HELLO DOCTOR VANAKKAM,

Warm welcome to stencildent family 

Contents:

v Introduction to casting procedure

v Sprue

v Specification of sprue

v Methods to prevent

v Function of sprue

v HAND WRITTEN NOTES

Introduction :

vCasting procedure steps:

1) Tooth preparation

2) Impression

3) Die preparation

4) Wax pattern

5) Sprue former

6) Casting ring liner

7) Investing

8) Wax elimination and burnout

9) Casting

10)Quenching

11)Sandblasting

12)Finishing and polishing

 

SPRUE

·       It’s a channel created in the investment through which molten alloy enter the mould space which is created due to burnout of wax pattern.

·       Sprue former are material used to form sprue

·       They are made up of wax, metal,resin.

SPECIFICATION OF SPRUE:

1)   SPRUE DIAMETER:

Ø Same a size as thickest area of wax pattern

Ø If large cause distortion

Ø Small : suck back porosity

2)   Sprue position :

Ø At greatest bulk in pattern

Ø The reasons are :

Ø To permit flow of alloy into the mould cavity

Ø To avoid distorting thin areas of wax

3)   Sprue length:

Ø In gypsum bonded investment material up to 6mm

Ø For phosphate bonded investment material about 3-4 mm and it should be placed in centre of ring

1)   SPRUE DIRECTION:

Ø      proximal surface -45 degree

Ø  135 degree to axial wall pattern

Methods to prevent:

§  Air entrapment

§  Occurrence of suck back porosity

Functions of sprue :

ü It forms mount for wax pattern

ü Channel for elimination of wax

ü Entry of molten alloy during casting

ü Compensate shrinkage during solidification




I Hope this short notes must have helped you if it had helped you do let me know in the comment section below as this will motivate  me to post more such content

For further contact me through contact information provided in the contact us page .

Thank you have a wonderful day

 


Comments

Post a Comment

Popular posts from this blog

Sterilization technique in microbiology

-
Image
HELLO! DOCTOR VANAKAM, I hope you all are doing good today we will be discussing sterilization various methods of sterilization, about dry heat sterilization and moist heat sterilization along with different methods employed, and what are the materials to be placed in this method in detail about autoclave its principle, working and of course uses. As I have had already informed you all through my previous post on the contribution of Louis Pasteur and Koch postulates if we haven't checked it out yet do check it out using this link   https://www.stencildent.com/2020/07/contributions-of-louis-pasteur-and-koch.html  wherein I would explain the importance for the need of the HOUR and always to sterilize things to and from the patients and also get geared up for the next post on SHOCK wherein I would cover the definition, types, classification along with etiology, pathogenesis, flow chart, the complication of septic shock in detail so now without any further ado lets get started. STERILI
Read more

STAGES AND STEPS IN TOOTH PREPARATION

-
Image
                      STAGES AND STEPS IN                                        TOOTH  PREPARATION                 TOOTH PREPARATION INVOLVES 2 STAGES  1) INITIAL TOOTH PREPARATION:    OUTLINE FORM AND INITIAL DEPTH PRIMARY RESISTANCE FORM  PRIMARY RETENTION FORM CONVENIENCE FORM 2) FINAL TOOTH PREPARATION  REMOVAL OF REMAINING CARIES PULP PROTECTION SECONDARY RESISTANCE AND RETENTION FORM FINISHING OF EXTERNAL WALL FINAL PROCEDURE OF CLEANING AND INSPECTING  Each stage and step is explained in detail please refer to above notes . note:please do not  download and share all rights are reserved to stencildent.
Read more

Hypersensitivity microbiology notes

-
Image
                          HYPERSENSITIVITY   hello, doctor vanakam, I hope you all are doing good, as intimated through the last post on anaerobic culture method  https://www.stencildent.com/2020/08/anaerobic-culture-methods-microbiology.html  if u haven't checked it out do read using this link without any further ado lets get started. CONTENTS: 1)Definition 2)Classification 3)type 1 hypersensitivity reaction a)1st exposure b)2nd exposure c)mediators of reaction d)late-phase reaction 4)type 4 hypersensitivity 5)treatment  1)DEFINITION: It refers to a condition in which immune response results in excessive reaction leading to tissue damage, disease, or even death in a sensitised host. 2) CLASSIFICATION: Coomb and gel classification in 1963 into type 1 to 4  Type 1,    type 2, type 3       : They depend on the interaction of antigen with humoral antibodies They are the immediate-type reaction  type 4 : They are mediated by t lymphocyte Delayed-type of hypersensitive reaction 3)TYPE 1
Read more