why is it slow to instantiate

so, i'm trying to instantiate an object but it so slow to instantiate, i need to wait 1 second after pressing one of the keyCode before i can instantiate

here's the codes: this is for the gameManager

 public class spawn : MonoBehaviour {
 
     public int tipe;
     public int objID;
     public Sprite spr;
     public Sprite battery;
     public Sprite adaptor;
     public KeyCode r;
     public KeyCode e;
 
     // Use this for initialization
     void Start () {
         
     }
     
     // Update is called once per frame
     void Update () {
 
         if (Input.GetKeyDown (r)) {
             tipe = 1;
             objID = 1;
             spr = battery;
         }
 
         if (Input.GetKeyDown (e)) {
             tipe = 2;
             objID = 2;
             spr = adaptor;
         }
     }
 }

this one is for the object that's going to instantiate

 public class preview : MonoBehaviour {
 
     public int tipe2;
     public bool start = false;
     SpriteRenderer sp;
     Color g = Color.green;
     GameObject gm;
 
     // Use this for initialization
     void Start () {
         sp = gameObject.GetComponent<SpriteRenderer> ();
         gm = GameObject.Find ("gameManager");
     }
     
     // Update is called once per frame
     void Update () {
         if (tipe2 == gm.GetComponent<spawn> ().tipe) {
             start = true;
             sp.sprite = gm.GetComponent<spawn> ().spr;
         } else {
             sp.sprite = null;
             start = false;
         }
 
         sp.color = g;
         g.a = 0.25f;
     }
 }

and this last one is also for the instantiator

 public class create : MonoBehaviour {
 
     public GameObject bat;
     public GameObject adpt;
     GameObject a;
     
     void OnMouseDown () {
         if (gameObject.GetComponent<preview> ().start) {
             if (GameObject.Find ("gameManager").GetComponent<spawn> ().objID == 1)
                 a = Instantiate (bat, transform.position, transform.rotation) as GameObject;
         
             if (GameObject.Find ("gameManager").GetComponent<spawn> ().objID == 2)
                 a = Instantiate (adpt, transform.position, transform.rotation) as GameObject;
 
             GameObject.Find ("gameManager").GetComponent<spawn> ().objID = 0;
             GameObject.Find ("gameManager").GetComponent<spawn> ().tipe = 0;
 
         }
     }
 }